Asymmetry of a complex gap near the Fermi level, determined from measurements of the thermopower in La1-xCaxMn1-yFeyO3

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Asymmetry of a complex gap near the Fermi level, determined from measurements of the thermopower in La_1-xCa_xMn_1-yFe_yO₃. / Laiho, R.; Lisunov, K. G.; Lähderanta, E.; Stamov, V. N.; Zakhvalinskii, V. S.; Kurbakov, A. I.; Sokolov, A. E.

в: Journal of Physics Condensed Matter, Том 16, № 6, 18.02.2004, стр. 881-890.

Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование

Author

Laiho, R. ; Lisunov, K. G. ; Lähderanta, E. ; Stamov, V. N. ; Zakhvalinskii, V. S. ; Kurbakov, A. I. ; Sokolov, A. E. / Asymmetry of a complex gap near the Fermi level, determined from measurements of the thermopower in La_1-xCa_xMn_1-yFe_yO₃. в: Journal of Physics Condensed Matter. 2004 ; Том 16, № 6. стр. 881-890.

BibTeX

@article{1c14d95d891d4385977b0caa84390448,

title = "Asymmetry of a complex gap near the Fermi level, determined from measurements of the thermopower in La1-xCaxMn1-yFeyO3",

abstract = "The thermopower, S, of La0.7Ca0.3Mn1-yFeyO3 (y = 0-0.09), measured for T = 25-310 K and magnetic fields of B = 0-10 T, exhibits strong sensitivity to doping with Fe. The weak increase of S observed in the undoped material with lowering temperature is enhanced considerably in the sample with y = 0.03 until a steep decrease takes place in the vicinity of the paramagnetic-ferromagnetic transition temperature, TC. S increases with further growth of y and its maximum follows the decrease of TC from 228 K at y = 0.03 to 119 K at y = 0.09. Application of a magnetic field reduces S strongly. The experimental data are analysed quantitatively with a percolation model using results of our recent investigations of the Shklovskii-Efros-like variable-range hopping conductivity in the same set of La1-xCaxMn1-yFeyO3 samples with evidence for a soft Coulomb gap and a rigid gap in the density of states near the Fermi level (Laiho et al 2002 J. Phys.: Condens. Matter 14 8043). In the paramagnetic insulating phase the temperature dependence of S is determined by competing contributions from two types of asymmetry of the gap: a small shift of its centre with respect to the Fermi level and cubic non-parabolicity. Numerical values of the shift and the cubic asymmetry terms are determined.",

author = "R. Laiho and Lisunov, {K. G.} and E. L{\"a}hderanta and Stamov, {V. N.} and Zakhvalinskii, {V. S.} and Kurbakov, {A. I.} and Sokolov, {A. E.}",

year = "2004",

month = feb,

day = "18",

doi = "10.1088/0953-8984/16/6/016",

language = "English",

volume = "16",

pages = "881--890",

journal = "Journal of Physics Condensed Matter",

issn = "0953-8984",

publisher = "IOP Publishing Ltd.",

number = "6",

}

RIS

TY - JOUR

T1 - Asymmetry of a complex gap near the Fermi level, determined from measurements of the thermopower in La1-xCaxMn1-yFeyO3

AU - Laiho, R.

AU - Lisunov, K. G.

AU - Lähderanta, E.

AU - Stamov, V. N.

AU - Zakhvalinskii, V. S.

AU - Kurbakov, A. I.

AU - Sokolov, A. E.

PY - 2004/2/18

Y1 - 2004/2/18

N2 - The thermopower, S, of La0.7Ca0.3Mn1-yFeyO3 (y = 0-0.09), measured for T = 25-310 K and magnetic fields of B = 0-10 T, exhibits strong sensitivity to doping with Fe. The weak increase of S observed in the undoped material with lowering temperature is enhanced considerably in the sample with y = 0.03 until a steep decrease takes place in the vicinity of the paramagnetic-ferromagnetic transition temperature, TC. S increases with further growth of y and its maximum follows the decrease of TC from 228 K at y = 0.03 to 119 K at y = 0.09. Application of a magnetic field reduces S strongly. The experimental data are analysed quantitatively with a percolation model using results of our recent investigations of the Shklovskii-Efros-like variable-range hopping conductivity in the same set of La1-xCaxMn1-yFeyO3 samples with evidence for a soft Coulomb gap and a rigid gap in the density of states near the Fermi level (Laiho et al 2002 J. Phys.: Condens. Matter 14 8043). In the paramagnetic insulating phase the temperature dependence of S is determined by competing contributions from two types of asymmetry of the gap: a small shift of its centre with respect to the Fermi level and cubic non-parabolicity. Numerical values of the shift and the cubic asymmetry terms are determined.

AB - The thermopower, S, of La0.7Ca0.3Mn1-yFeyO3 (y = 0-0.09), measured for T = 25-310 K and magnetic fields of B = 0-10 T, exhibits strong sensitivity to doping with Fe. The weak increase of S observed in the undoped material with lowering temperature is enhanced considerably in the sample with y = 0.03 until a steep decrease takes place in the vicinity of the paramagnetic-ferromagnetic transition temperature, TC. S increases with further growth of y and its maximum follows the decrease of TC from 228 K at y = 0.03 to 119 K at y = 0.09. Application of a magnetic field reduces S strongly. The experimental data are analysed quantitatively with a percolation model using results of our recent investigations of the Shklovskii-Efros-like variable-range hopping conductivity in the same set of La1-xCaxMn1-yFeyO3 samples with evidence for a soft Coulomb gap and a rigid gap in the density of states near the Fermi level (Laiho et al 2002 J. Phys.: Condens. Matter 14 8043). In the paramagnetic insulating phase the temperature dependence of S is determined by competing contributions from two types of asymmetry of the gap: a small shift of its centre with respect to the Fermi level and cubic non-parabolicity. Numerical values of the shift and the cubic asymmetry terms are determined.

UR - http://www.scopus.com/inward/record.url?scp=1442336119&partnerID=8YFLogxK

U2 - 10.1088/0953-8984/16/6/016

DO - 10.1088/0953-8984/16/6/016

M3 - Article

AN - SCOPUS:1442336119

VL - 16

SP - 881

EP - 890

JO - Journal of Physics Condensed Matter

JF - Journal of Physics Condensed Matter

SN - 0953-8984

IS - 6

ER -

ID: 99520407