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1.


    Valkov, V. V.
    Application of indefinite metric for transition to bose description of Su(3) hamiltonians - excitation spectrum of spin nematics / V. V. Valkov, T. A. Valkova // Zhurnal Eksperimentalnoi Teor. Fiz. - 1991. - Vol. 99, Is. 6. - P. 1881-1897. - Cited References: 37 . - ISSN 0044-4510
РУБ Physics, Multidisciplinary
Рубрики:
BIQUADRATIC EXCHANGE
   PHASE-TRANSITIONS

   DIAGRAM TECHNIQUE

   MAGNETISM

   FIELD

   STATE

Аннотация: A procedure is developed for a correct transition to the Bose representation for quantum SU(3) Hamiltonians. The analysis is carried out for a spin nematic by applying the indefinite metric formalism and pseudo-Hubbard operators. An important aspect of the theory is that the finiteness of the number of physical states is taken into account. This is attained by introducing and consistently taking into account the metric operator for which purpose a simple expression in terms of Bose operators is suggested. It is shown that in this approach the quantum Bose analog of the Hamiltonian is an Hermitian operator. This circumstance removes a number of principle contradictions which appeared previously on application of the Bose analog of the Hamiltonian derived by virtually identifying the Hubbard and pseudo-Hubbard operators and ignoring the finiteness of the number of physical states. The integral equations defining the chief characteristics of the system are obtained and solved analytically for the spin-nematic state of a magnet with S = 1 and by taking into account anharmonic effects. This permits one to write down in nonlinear theory explicit expressions for the two branches of the quantum excitation spectrum. The character of the renormalization of the spectrum parameters due to the presence of zero-point quantum oscillations is studied. The renormalization of the critical field on transition of the system from the spin nematic state is calculated analytically.

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Доп.точки доступа:
Valkova, T. A.; Вальков, Валерий Владимирович
}
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2.


    GEKHT, R. S.
    MAGNETIC-STRUCTURES AND PROPERTIES OF STATES IN STRONGLY FRUSTRATED HEISENBERG ANTIFERROMAGNETS / R. S. GEKHT // Zhurnal Eksperimentalnoi Teor. Fiz. - 1992. - Vol. 102, Is. 6. - P. 1968-1982. - Cited References: 23 . - ISSN 0044-4510
РУБ Physics, Multidisciplinary
Рубрики:
PHASE-TRANSITIONS
   SPIN

   LATTICE

   MODELS

   LONG

Аннотация: The magnetic structures and properties of states in frustrated Heisenberg antiferromagnets are analyzed. It is shown that frustrations induced due to additional spins in the system lead to a large variety of phase with the commensurable and uncommensurable periods and also to arising nonperiodical phases. The energy spectrum of states is studied. It is found that in the large region of the frustration parameter variation the modulated phase (0, Q) is unstable. The phase diagram of states is found and the region of local degeneration for some structures is indicated.

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3.


    GEKHT, R. S.
    ON MAGNETIC STATES IN STRONGLY FRUSTRATED 2-DIMENSIONAL ANTIFERROMAGNETICS / R. S. GEKHT, V. V. GRISHIN // Fiz. Tverd. Tela. - 1992. - Vol. 34, Is. 11. - P. 3557-3559. - Cited References: 5 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   LATTICE


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Держатели документа:
LV KIRENSKII INST PHYS,KRASNOYARSK,RUSSIA
ИФ СО РАН

Доп.точки доступа:
GRISHIN, V. V.
}
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4.


    GEKHT, R. S.
    LOW-TEMPERATURE PROPERTIES OF QUASI-2-DIMENSIONAL FRUSTRATED ANTI-FERROMAGNETICS / R. S. GEKHT, V. I. PONOMAREV // Fiz. Tverd. Tela. - 1994. - Vol. 36, Is. 11. - P. 3394-3397. - Cited References: 8 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   MAGNETIC STATES

   ANTIFERROMAGNETS


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Доп.точки доступа:
PONOMAREV, V. I.
}
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5.


   
    Study of molecular mobility in ABF6-center-dot-6H2O crystal family / E. P. Zeer, O. V. Falaleev, Y. N. Ivanov, E. A. Petrakovskaya // Fiz. Tverd. Tela. - 1994. - Vol. 36, Is. 8. - P. 2210-2220. - Cited References: 21 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   NMR

   SYSTEM


WOS

Доп.точки доступа:
Zeer, E. P.; Зеер, Эвальд Петрович; Falaleev, O. V.; Фалалеев, Олег Владимирович; Ivanov, Y. N.; Иванов, Юрий Николаевич; Petrakovskaya, E. A.; Петраковская, Элеонора Анатольевна
}
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6.


    Gekht, R. S.
    Helicoidal magnetic structure in frustrated antiferromagnetics / R. S. Gekht, A. M. Epikhin, V. I. Ponomarev // Fiz. Tverd. Tela. - 1995. - Vol. 37, Is. 6. - P. 1891-1893. - Cited References: 6 . - ISSN 0367-3294
РУБ Physics, Condensed Matter
Рубрики:
QUANTUM FLUCTUATIONS
   PHASE-TRANSITIONS


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Доп.точки доступа:
Epikhin, A. M.; Ponomarev, V. I.
}
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7.


   
    Chemical exchange in NH4HSeO4 single crystals studied by two-dimensional H-2 nuclear magnetic resonance / Y. N. Ivanov [et al.] // J. Phys.: Condens. Matter. - 1999. - Vol. 11, Is. 18. - P. 3751-3760, DOI 10.1088/0953-8984/11/18/310. - Cited References: 16 . - ISSN 0953-8984
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   CONDUCTIVITY PROCESSES

   AMMONIUM

Кл.слова (ненормированные):
Hydrogen bonds -- Nuclear magnetic resonance -- Single crystals -- Thermal effects -- Ammonium hydrogen selenate -- Ammonium compounds
Аннотация: Processes of chemical exchange of deuterons in partially deuterated ammonium hydrogen selenate, NH4HSeO4 (AHSe), crystals are investigated by means of H-2 nuclear magnetic resonance (NMR) experiments over a wide temperature range. The temperature dependencies of the quadrupole line splittings in the one-dimensional spectra of AHSe above 350 K revealed lineshape changes which are characteristic for chemical exchange processes. A detailed study of these exchange processes in AHSe is achieved by means of two-dimensional H-2 NMR experiments. In the temperature range investigated, a chemical exchange occurs only between those deuteron (proton) sites which are involved in hydrogen bonds (alpha- and beta-positions). It was established that the rates of exchange between all types of hydrogen-bound deuteron are approximately the same. Exchange between these positions and the deuterons in the ND4 groups could not be detected. On the basis of our findings, we finally discuss a model for the microscopic mechanism of hydrogen transport in AHSe.

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Держатели документа:
LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
Univ Leipzig, Fak Phys & Geowissensch, D-04103 Leipzig, Germany
ИФ СО РАН
L V Kirensky Institute of Physics, Russian Academy of Science, Siberian Branch, 660036 Krasnoyarsk, Russian Federation
Universitat Leipzig, Fakultat fur Physik und Geowissenschaften, Linnestra?e 5, D-04103 Leipzig, Germany

Доп.точки доступа:
Ivanov, Y. N.; Иванов, Юрий Николаевич; Totz, J.; Michel, D.; Klotzsche, G.; Sukhovsky, A. A.; Суховский, Андрей Андреевич; Aleksandrova, I. P.; Александрова, Инга Петровна
}
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8.


    Ovchinnikov, S. G.
    Application of synchrotron radiation to the study of magnetic materials / S. G. Ovchinnikov // Uspekhi Fiz. Nauk. - 1999. - Vol. 169, Is. 8. - P. 869-887. - Cited References: 93 . - ISSN 0042-1294
РУБ Physics, Multidisciplinary
Рубрики:
X-RAY-SCATTERING
   RESONANCE EXCHANGE SCATTERING

   RARE-EARTH-METALS

   CIRCULAR-DICHROISM

   VALENCE STATES

   CO/PD(111) MULTILAYERS

   ABSORPTION-SPECTRA

   PHASE-TRANSITIONS

   SPIN POLARIZATION

   EDGE STRUCTURE

Аннотация: The recent results of the studies of magnetic materials using synchrotron irradiation are reviewed. The influence of magnetic effects on X-ray scattering is studied for linearly and circularly polarized photons, and effects of magnetic circular dichroism on the spectra of X-ray absorption and photoelectron emission are discussed. It is shown that X-ray magnetooptics techniques provide fine details of crystal and magnetic structures and also make it possible to separate the spin and orbital contributions to the total moment; to obtain element- and position-sensitive information on the magnetic properties of the material; to visualize domains and domain walls; and to probe magnetization reversal dynamics. A comparison of magnetic neutron and X-ray methods is given.

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Держатели документа:
Russian Acad Sci, Siberian Div, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
ИФ СО РАН
L.V. Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Овчинников, Сергей Геннадьевич
}
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9.


   
    Thermodynamic properties of (NH4)(2)KGaF6 elpasolite / I. N. Flerov [et al.] // Phys. Solid State. - 2001. - Vol. 43, Is. 12. - P. 2301-2306, DOI 10.1134/1.1427960. - Cited References: 19 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
NUCLEAR MAGNETIC-RESONANCE
   PHASE-TRANSITIONS

   CRYOLITE (NH4)(3)SCF6

   MOTIONS

   F-19

   H-1

Аннотация: The heat capacity of (NH4)(2)KGaF6 elpasolite is measured in the temperature range from 80 to 350 K. A sequence of three phase transitions at T-1 = 288.5 K, T-2 = 250 K, and T-3 = 244.5 K is revealed, and the thermodynamic characteristics of these transitions are determined. The influence of hydrostatic pressure on the phase transition temperature is investigated. The results obtained are discussed within the model of orientational ordering of NH4+ and GaF63- ionic groups. (C) 2001 MAIK "Nauka/Interperiodica".

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Afanas'ev, M. L.; Ushakova, T. V.
}
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10.


   
    Low-temperature specific heat of the Rb2KScF6 elpasolite / I. N. Flerov [et al.] // Phys. Solid State. - 2003. - Vol. 45, Is. 1. - P. 167-170, DOI 10.1134/1.1537430. - Cited References: 9 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   CRYOLITE (NH4)(3)SCF6

   DISTORTED PHASES

   SYMMETRY

Аннотация: The specific heat of single-crystal Rb2KScF6 is measured using ac calorimetry in the range 4-280 K. The results are discussed in the context of a group-theoretical analysis of possible distortions of the elpasolite structure and of experimental data obtained earlier with an adiabatic calorimeter in a narrower temperature region. (C) 2003 MAIK "Nauka/Interperiodica".

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Держатели документа:
Russian Acad Sci, Siberian Div, Kirenskii Inst Phys, Krasnoyarsk 660036, Russia
Univ Zaragoza, CSIC, Inst Sci Mat Aragon, E-50009 Zaragoza, Spain
ИФ СО РАН
Kirenskii Inst. of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036, Russian Federation
Inst. de Sciencia de Mat. de Aragon, CSIC, Universidad de Zaragoza, Zaragoza 50009, Spain

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Burriel, R.; Gorev, M. V.; Горев, Михаил Васильевич; Isla, P.; Voronov, V. N.; Воронов, Владимир Николаевич
}
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11.


   
    Calorimetric and x-ray diffraction studies of the (NH4)(3)WO3F3 and (NH4)(3)TiOF5 perovskite-like oxyfluorides / I. N. Flerov [et al.] // Phys. Solid State. - 2004. - Vol. 46, Is. 5. - P. 915-921, DOI 10.1134/1.1744971. - Cited References: 11 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   ELPASOLITE

   K3MOO3F3

Аннотация: The heat capacity and unit cell parameters of the (NH4)(3)WO3F3 and (NH4)(3)TiOF5 perovskite-like oxyfluorides were measured in the temperature interval from 80 to 300 K; the existence of two and one phase transitions in these compounds, respectively, was demonstrated, and their thermodynamic parameters were determined. The effect of a hydrostatic pressure of up to 0.5 GPa on the phase transition temperatures was studied. Triple points and high-pressure phases were found in the T vs. p diagrams. An analysis of entropy changes suggests that all the structural transformations revealed are associated with the ordering of structural blocks. (C) 2004 MAIK "Nauka / Interperiodica".

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Держатели документа:
Russian Acad Sci, Siberian Div, LV Kirensky Phys Inst, Krasnoyarsk 660036, Russia
Russian Acad Sci, Inst Chem, Far E Div, Vladivostok 690022, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Institute of Chemistry, Far East Division, Russian Academy of Sciences, pr. Stoletiya Vladivostoka 159, Vladivostok, 690022, Russian Federation

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Gorev, M. V.; Горев, Михаил Васильевич; Fokina, V. D.; Фокина, Валентина Дмитриевна; Bovina, A. F.; Бовина, Ася Федоровна; Laptash, N. M.
}
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12.


    Flerov, I. N.
    Calorimetric and optical studies of orthorhombic and cubic CsLiCrO4 crystals / I. N. Flerov, A. V. Kartashev, S. V. Mel'nikova // Phys. Solid State. - 2006. - Vol. 48, Is. 11. - P. 2171-2176, DOI 10.1134/S1063783406110242. - Cited References: 23 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   X-RAY

   NH4LISO4

   ALPHA

Аннотация: Careful calorimetric and polarization optical studies of a metastable cubic modification of a CsLiCrO4 crystal (space group (F43m)) are performed. Anomalies of the heat capacity indicative of structural distortions at 92.4 and 69.1 K were revealed, and the values of the thermodynamic parameters of the phase transitions were determined. The crystal twinning in the intermediate phase was studied. A comparative analysis of the phase transitions occurring in a series of ALiMO(4) crystals (A=NH4, Cs; M=S, Cr, Mo, W) was performed. First studies of the monotropic structural transformation F43m - Pmcn and the enantiotropic phase transition Pmcn reversible arrow P112(1)/n were carried out using scanning calorimetry, and the thermodynamic parameters of these transitions were determined.

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Держатели документа:
Russian Acad Sci, LV Kirensky Phys Inst, Siberian Div, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation

Доп.точки доступа:
Kartashev, A. V.; Карташев, Андрей Васильевич; Mel'nikova, S. V.; Мельникова, Светлана Владимировна; Флёров, Игорь Николаевич
}
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13.


   
    Raman spectra and ordering processes in alcaline-tungsten oxyfluorides / K. S. Aleksandrov [et al.] // Ferroelectrics. - 2007. - Vol. 347. - P. 79-85, DOI 10.1080/00150190601187070. - Cited References: 8 . - ISSN 0015-0193
РУБ Materials Science, Multidisciplinary + Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   ELPASOLITES

Аннотация: Raman spectra of perovskite-like (NH4)(3)WO3F3 (assigned below as A3), (NH4)(2)KWO3F3 (A2K), Cs-2(NH4)WO3F3 (C2A) oxyfluorides are obtained in a wide temperature range including transition points for A3 and A2 K crystals. Transition anomalies are found and analyzed. Transformation in A3 crystal is shown to be bound with octahedron groups ordering and H-bond formation, that is accompanied by cell volume multiplication, hardening and formation of complex discrete low frequency lattice spectrum. Same cell doubling was found in A2 K crystal, but without lattice ordering. C2A lattice stays disordered down to 15 K.

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Доп.точки доступа:
Aleksandrov, K. S.; Александров, Кирилл Сергеевич; Vtyurin, A. N.; Втюрин, Александр Николаевич; Gerasimova, J. V.; Герасимова, Юлия Валентиновна; Krylov, A. S.; Крылов, Александр Сергеевич; Laptash, N. M.; Voyt, E. I.; Kocharova, A. G.; Кочарова, Алла Георгиевна; Surovtsev, S. V.; Russian-CIS-Baltic-Japanese symposium on ferroelectricity(8 ; 2006 ; May ; 15-19 ; Tsukuba, Japan)
}
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14.


   
    Effect of deuteration on the thermal properties and structural parameters of the (NH4)(2)WO2F4 oxyfluoride / I. N. Flerov [et al.] // Phys. Solid State. - 2007. - Vol. 49, Is. 6. - P. 1149-1156, DOI 10.1134/S1063783407060212. - Cited References: 11 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PEROVSKITE-LIKE OXYFLUORIDES
   PHASE-TRANSITIONS

   (NH4)(3)WO3F3

   (NH4)(3)TIOF5

Аннотация: The thermal properties and structure of (ND4)(2)WO2F4 crystals are investigated. It is established that deuteration does not lead to a change in the symmetry of the initial phase Cmcm but considerably decreases the extent of its disordering, which, in turn, brings about a substantial decrease in the phase transition entropy. Apart from the anomalies associated with phase transitions characteristic of the protonic compound, the heat capacity exhibits two additional anomalies. Analysis of the phase diagram of the deuterated crystal reveals a triple point at a pressure p = 0.18 GPa, which is predicted for (NH4)(2)WO2F4 at about 0.7 GPa.

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Держатели документа:
LV Kirenskii Inst Phys, Russian Acad Sci, Siberian Div, Krasnoyarsk 660036, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation

Доп.точки доступа:
Flerov, I. N.; Флёров, Игорь Николаевич; Fokina, V. D.; Фокина, Валентина Дмитриевна; Gorev, M. V.; Горев, Михаил Васильевич; Bogdanov, E. V.; Богданов, Евгений Витальевич; Molokeev, M. S.; Молокеев, Максим Сергеевич; Bovina, A. F.; Бовина, Ася Федоровна; Kocharova, A. G.; Кочарова, Алла Георгиевна
}
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15.


    Flerov, I. N.
    Electrocaloric effect and anomalous conductivity of the ferroelectric NH4HSO4 / I. N. Flerov, E. A. Mikhaleva // Phys. Solid State. - 2008. - Vol. 50, Is. 3. - P. 478-484, DOI 10.1134/S1063783408030141. - Cited References: 10 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
Аннотация: An intensive electrocaloric effect in the uniaxial ferroelectric NH4HSO4 near the second-order phase transition (T-1 approximate to 271 K) is studied. A high electrical conductivity of the NH4HSO4 crystal is revealed, and its temperature dependence is investigated. The results obtained are analyzed together with the data available for the ferroelectrics, which hold promise for the use as solid-state cooling agents.

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Держатели документа:
[Flerov, I. N.] Russian Acad Sci, Kirensky Inst Phys, Siberian Branch, Krasnoyarsk 660036, Russia
[Mikhaleva, E. A.] Siberian Fed Univ, Polytech Inst, Krasnoyarsk 660074, Russia
ИФ СО РАН

Доп.точки доступа:
Mikhaleva, E. A.; Михалева, Екатерина Андреевна; Флёров, Игорь Николаевич
}
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16.


   
    Na-23 NMR study of the local order in the Na1/2Bi1/2TiO3 structure in a weak magnetic field / I. P. Aleksandrova [et al.] // Phys. Solid State. - 2008. - Vol. 50, Is. 3. - P. 496-501, DOI 10.1134/S1063783408030177. - Cited References: 14 . - ISSN 1063-7834
РУБ Physics, Condensed Matter
Рубрики:
PHASE-TRANSITIONS
   PEROVSKITE

Аннотация: The orientation dependences of the second-order quadrupole shifts of the central component in the Na-23 NMR spectrum were studied in the temperature range 293-760 K. The profile of the spectral distribution is calculated using various models of the Na1/2Bi1/2TiO3 structure. The calculations agree with the experimental data for the monoclinic structure of a polar cluster with two Na displacement components: a displacement along the [111](P) direction and a small displacement statistically or dynamically disordered over six equally probable [100](P)-type directions. Tetragonal-phase nuclei and monoclinic clusters with a very small displacement component along the [111](P) direction are found to coexist and have close energies over the temperature range 580-610 K. The results obtained provide new information concerning the character of the diffuse phase transition at 610 K.

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Держатели документа:
[Aleksandrova, I. P.
Sukhovskii, A. A.
Ivanov, Yu. N.
Yablonskaya, Yu. E.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Vakhrushev, S. B.] Russian Acad Sci, AF Ioffe Physicotech Inst, St Petersburg 194021, Russia
ИФ СО РАН

Доп.точки доступа:
Aleksandrova, I. P.; Александрова, Инга Петровна; Sukhovskii, A. A.; Суховский, Андрей Андреевич; Ivanov, Y. N.; Иванов, Юрий Николаевич; Yablonskaya, Y. E.; Vakhrushev, S. B.
}
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17.


    Shneyder, E. I.
    Isotope effect in the model of strongly correlated electrons with the magnetic and phonon superconducting pairing mechanisms / E. I. Shneyder, S. G. Ovchinnikov // J. Exp. Theor. Phys. - 2009. - Vol. 109, Is. 6. - P. 1017-1021, DOI 10.1134/S1063776109120139. - Cited References: 42. - This study was financed under programs 5.7 and "Quantum Physics of Condensed Matter" of the Presidium of the Russian Academy of Sciences, integration project no. 40 of the Siberian Branch and Ural Division of the Russian Academy of Sciences, and the Russian Foundation for Basic Research (project no. 09-02-00127). . - ISSN 1063-7761
РУБ Physics, Multidisciplinary
Рубрики:
CUPRATE SUPERCONDUCTORS
   PHASE-TRANSITIONS

   3-CENTER INTERACTIONS

   HUBBARD-MODEL

   TEMPERATURE

   LA2-XSRXCUO4

   SYMMETRY

   EXCHANGE

   COPPER

   BI2SR2CACU2O8+DELTA

Кл.слова (ненормированные):
Ab initio calculations -- Calculated values -- Cooper pairing -- Isotope effect -- Magnetic mechanisms -- Order of magnitude -- Pairing mechanism -- Phonon mechanism -- Strongly correlated electrons -- Superconducting pairing mechanism -- Superconducting state -- Type theory -- Carrier mobility -- Electron-phonon interactions -- Isotopes -- Superconductivity -- Superconducting magnets
Аннотация: Peculiarities of the temperature isotope effect in a BCS-type theory describing the exchange and phonon mechanisms of Cooper pairing in a system of strongly correlated electrons are considered. The electron-phonon interaction constant is determined from the fitting of the calculated value of the isotope-effect index to the observed value with the parameters of La(2 - x) Sr (x) CuO(4) obtained from ab initio calculations. The value of this constant indicates that the contribution from the traditional pairing mechanism to the superconducting state is of the same order of magnitude as the contribution from the magnetic mechanism.

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Публикация на русском языке Шнейдер, Елена Игоревна. Изотопический эффект в модели сильно коррелированных электронов, учитывающей магнитный и фононный механизмы сверхпроводящего спаривания [Текст] / Е. И. Шнейдер, С. Г. Овчинников // Журн. эксперим. и теор. физ. - 2009. - Т. 136 Вып. 6. - С. 1177-1182

Держатели документа:
[Shneyder, E. I.
Ovchinnikov, S. G.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Shneyder, E. I.] Siberian State Aerosp Univ, Krasnoyarsk 660014, Russia
[Ovchinnikov, S. G.] Siberian Fed Univ, Krasnoyarsk 660041, Russia
ИФ СО РАН
Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russian Federation
Siberian State Aerospace University, Krasnoyarsk, 660014, Russian Federation
Siberian Federal University, Krasnoyarsk, 660041, Russian Federation

Доп.точки доступа:
Ovchinnikov, S. G.; Овчинников, Сергей Геннадьевич; Шнейдер, Елена Игоревна; Presidium of the Russian Academy of Sciences [40]; Russian Academy of Sciences; Russian Foundation for Basic Research [09-02-00127]
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18.


   
    Magnetoelectric effect and spontaneous polarization in HoFe3(BO3)(4) and Ho0.5Nd0.5Fe3(BO3)(4) / R. P. Chaudhury [et al.] // Phys. Rev. B. - 2009. - Vol. 80, Is. 10. - Ст. 104424, DOI 10.1103/PhysRevB.80.104424. - Cited References: 35. - This work is supported in part by NSF Grant No. DMR9804325, the T. L. L. Temple Foundation, the J.J. and R. Moores Endowment, and the State of Texas through the TC-SUH and at LBNL by the DoE. . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
IRON BORATE GDFE3(BO3)(4)
   PHASE-TRANSITIONS

   NDFE3(BO3)(4)

   MULTIFERROICS

Аннотация: The thermodynamic, magnetic, dielectric, and magnetoelectric properties of HoFe3(BO3)(4) and Ho0.5Nd0.5Fe3(BO3)(4) are investigated. Both compounds show a second order Neel transition above 30 K and a first-order spin reorientation transition below 10 K. HoFe3(BO3)(4) develops a spontaneous electrical polarization below the Neel temperature (T-N) which is diminished in external magnetic fields. No magnetic-field induced increase of the polarization could be observed in HoFe3(BO3)(4). In contrast, the solid solution Ho0.5Nd0.5Fe3(BO3)(4) exhibits both, a spontaneous polarization below T-N and a positive magnetoelectric effect at higher fields that extends to high temperatures. The superposition of spontaneous polarization, induced by the internal magnetic field in the ordered state, and the magnetoelectric polarizations due to the external field results in a complex behavior of the total polarization measured as a function of temperature and field.

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Держатели документа:
[Chaudhury, R. P.
Lorenz, B.
Sun, Y. Y.
Chu, C. W.] Univ Houston, TCSUH, Houston, TX 77204 USA
[Chaudhury, R. P.
Lorenz, B.
Sun, Y. Y.
Chu, C. W.] Univ Houston, Dept Phys, Houston, TX 77204 USA
[Yen, F.] SW Jiaotong Univ, Appl Superconduct Lab, Chengdu 610031, Sichuan, Peoples R China
[Bezmaternykh, L. N.
Temerov, V. L.] Russian Acad Sci, Inst Phys, Siberian Div, Krasnoyarsk 660036, Russia
[Chu, C. W.] Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA
[Chu, C. W.] Hong Kong Univ Sci & Technol, Hong Kong, Hong Kong, Peoples R China
ИФ СО РАН
TCSUH, Department of Physics, University of Houston, Houston, TX 77204-5002, United States
Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu, Sichuan 610031, China
Institute of Physics, Siberian Division, Russian Academy of Sciences, Krasnoyarsk 660036, Russian Federation
Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, United States
Hong Kong University of Science and Technology, Hong Kong, Hong Kong

Доп.точки доступа:
Chaudhury, R. P.; Yen, F.; Lorenz, B.; Sun, Y. Y.; Bezmaternykh, L. N.; Безматерных, Леонард Николаевич; Temerov, V. L.; Темеров, Владислав Леонидович; Chu, C. W.; NSF [DMR9804325]; Temple Foundation; State of Texas through the TC-SUH; DoE
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19.


   
    Nonanalytic Spin Susceptibility of a Fermi Liquid: The Case of Fe-Based Pnictides / M. M. Korshunov [et al.] // Phys. Rev. Lett. - 2009. - Vol. 102, Is. 23. - Ст. 236403, DOI 10.1103/PhysRevLett.102.236403. - Cited References: 41. - We thank R. Klingeler for useful discussions. M. M. K. acknowledges support from RFBR ( 09-02-00127) and the OFN RAS program on "Strong electronic correlations". I. E. acknowledges partial support from APCTP, NSF-DMR ( 0645461), and the RMHE Program ( Contract No. 2.1.1/3199). D. L. M. acknowledges support from Laboratoire de Physique des Solides, Universite Paris-Sud ( France) and RTRA Triangle de la Physique. A. V. C. acknowledges support from NSF-DMR 0604406. . - ISSN 0031-9007
РУБ Physics, Multidisciplinary
Рубрики:
PHASE-TRANSITIONS
   QUANTUM

Кл.слова (ненормированные):
Electron pockets -- Fermi energy -- Linear temperature dependence -- Pnictides -- Prefactor -- Quantitative agreement -- Spin susceptibility -- Temperature dependence -- Fermi liquids -- Fermions -- Liquids -- Magnetic susceptibility -- Temperature distribution -- Spin dynamics
Аннотация: We propose an explanation of the peculiar linear temperature dependence of the uniform spin susceptibility chi(T) in ferropnictides. We argue that the linear in T term appears to be due to the nonanalytic temperature dependence of chi(T) in a two-dimensional Fermi liquid. We show that the prefactor of the T term is expressed via the square of the spin-density-wave (SDW) amplitude connecting nested hole and electron pockets. Because of an incipient SDW instability, this amplitude is large, which, along with a small value of the Fermi energy, makes the T dependence of chi(T) strong. We demonstrate that this mechanism is in quantitative agreement with the experiment.

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Держатели документа:
[Korshunov, M. M.
Eremin, I.] Max Planck Inst Phys Komplexer Syst, D-01187 Dresden, Germany
[Korshunov, M. M.] Russian Acad Sci, LV Kirensky Phys Inst, Siberian Branch, Krasnoyarsk 660036, Russia
[Eremin, I.] Tech Univ Carolo Wilhelmina Braunschweig, Inst Math & Theoret Phys, D-38106 Braunschweig, Germany
[Efremov, D. V.] Tech Univ Dresden, Inst Theoret Phys, D-01062 Dresden, Germany
[Maslov, D. L.] Univ Florida, Dept Phys, Gainesville, FL 32611 USA
[Chubukov, A. V.] Univ Wisconsin, Dept Phys, Madison, WI 53706 USA
ИФ СО РАН
Max-Planck-Institut fur Physik Komplexer Systeme, D-01187 Dresden, Germany
L. V. Kirensky Institute of Physics, Siberian Branch, Russian Academy of Sciences, 660036 Krasnoyarsk, Russian Federation
Institute fur Mathematische und Theoretische Physik, Technische Universitat Braunschweig, 38106 Braunschweig, Germany
Institut fur Theoretische Physik, Technische Universitat Dresden, 01062 Dresden, Germany
Department of Physics, University of Florida, Gainesville, FL 32611, United States
Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, United States
Kazan State University, 420087 Kazan, Russian Federation

Доп.точки доступа:
Korshunov, M. M.; Коршунов, Максим Михайлович; Eremin, I.; Efremov, D. V.; Maslov, D. L.; Chubukov, A. V.; RFBR [09-02-00127]; OFN RAS; APCTP; NSF-DMR [0645461, 0604406]; RMHE [2.1.1/3199]; Laboratoire de Physique des Solides, Universite Paris-Sud (France); RTRA Triangle de la Physique
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20.


   
    Single magnetic chirality in the magnetoelectric NdFe3((BO3)-B-11)(4) / M. . Janoschek [et al.] // Phys. Rev. B. - 2010. - Vol. 81, Is. 9. - Ст. 94429, DOI 10.1103/PhysRevB.81.094429. - Cited References: 55 . - ISSN 1098-0121
РУБ Physics, Condensed Matter
Рубрики:
NEUTRON-DIFFRACTION
   PHASE-TRANSITIONS

   SLOW-NEUTRONS

   CRYSTAL

   NDFE3(BO3)(4)

   EXTINCTION

   NUCLEAR

   ORDER

   MNSI

   ANTIFERROMAGNETS

Аннотация: We have performed an extensive study of single crystals of the magnetoelectric NdFe3 ((BO3)-B-11)(4) by means of a combination of single-crystal neutron diffraction and spherical neutron polarimetry. Our investigation did not detect significant deviations at low temperatures from space group R32 concerning the chemical structure. With respect to magnetic ordering our combined results demonstrate that in the commensurate magnetic phase below T-N approximate to 30 K all three magnetic Fe moments and the magnetic Nd moment are aligned ferromagnetically in the basal hexagonal plane but align antiferromagnetically between adjacent planes. The phase transition to the low-temperature incommensurate (IC) magnetic structure observed at T-IC approximate to 13.5 K appears to be continuous. By means of polarized neutron studies it could be shown that in the incommensurate magnetic phase the magnetic structure of NdFe3((BO3)-B-11)(4) is transformed into a long-period antiferromagnetic helix with single chirality. Close to the commensurate-incommensurate phase transition third-order harmonics were observed, which in addition indicate the formation of magnetic solitons.

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Держатели документа:
[Janoschek, M.
Fischer, P.
Schefer, J.
Roessli, B.
Pomjakushin, V.] Paul Scherrer Inst, Neutron Scattering Lab, CH-5232 Villigen, Switzerland
[Janoschek, M.
Fischer, P.
Schefer, J.
Roessli, B.
Pomjakushin, V.] ETH, CH-5232 Villigen, Switzerland
[Janoschek, M.] Tech Univ Munich, Phys Dept E21, D-85748 Garching, Germany
[Meven, M.] Tech Univ Munich, Forsch Neutronenquelle Heinz Maier Leibnitz FRM 2, D-85748 Garching, Germany
[Petricek, V.] ASCR, Vvi, Inst Phys, Prague 18221 8, Czech Republic
[Petrakovskii, G.
Bezmaternikh, L.] RAS, SB, Inst Phys, Krasnoyarsk 660036, Russia
ИФ СО РАН
Laboratory for Neutron Scattering, Paul Scherrer Institut and ETH Zurich, CH-5232 Villigen PSI, Switzerland
Physik Department E21, Technische Universitat Munchen, D-85748 Garching, Germany
Department of Physics, University of California, San Diego, San Diego, CA 92093-0354, United States
Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitat Munchen, D-85748 Garching, Germany
Institute of Physics, ASCR, V.v.i, Na Slovance 2, 182 21 Praha 8, Czech Republic
Institute of Physics, SB RAS, Krasnoyarsk 660036, Russian Federation

Доп.точки доступа:
Janoschek, M.; Fischer, P.; Schefer, J.; Roessli, B.; Pomjakushin, V.; Meven, M.; Petricek, V.; Petrakovskii, G. A.; Петраковский, Герман Антонович; Bezmaternykh, L. N.; Безматерных, Леонард Николаевич
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