Magnetic properties and electronic structure of LaFeAsO0.85F0.1

Автор(и)

  • A.V. Fedorchenko B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • G.E. Grechnev B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • V.A. Desnenko B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • A.S. Panfilov B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • O.S. Volkova Department of Low Temperature Physics and Superconductivity, Physics Faculty, M.V. Lomonosov Moscow State University, Moscow 119899, Russia
  • A.N. Vasiliev Department of Low Temperature Physics and Superconductivity, Physics Faculty, M.V. Lomonosov Moscow State University, Moscow 119899, Russia

DOI:

https://doi.org/10.1063/1.3331507

Ключові слова:

FeAs superconductors, magnetic susceptibility, electronic structure.

Анотація

The magnetic properties of LaFeAsO0.85F0.1 compound were investigated by measurements of dc magnetization at different values of the magnetic field, H = 0.02, 1.0 and 2.0 T, in the temperature range 4.2–300 K. The superconducting behavior was found below 26 K, whereas a distinct peculiarity in the low-field dependence of the magnetic susceptibility c(T) was clearly observed at TM≃ 135 K, which resembles a weak ferromagnetic (FM) response with saturation magnetic moment of about 10–4 μB per formula unit at 50 K. The transition at TM is presumably not governed by magnetic impurities but rather correlated with the antiferromagnetic (AFM) transition in the undoped LaFeAsO compound at about the same temperature. We suggest, that observed magnetic properties of the LaFeAsO0.85F0.1 sample are due to an interplay of FM and AFM transitions, and presumably related to an intrinsic feature of a small portion of the undoped LaFeAsO phase inherent in our sample. In order to shed light on the problem of magnetic instability of the LaFeAsO, the ab initio DFT calculations of electronic structure and paramagnetic susceptibility were performed within the local spin density approximation. It is shown, that a V-shaped peculiarity in the density of electronic states in a close vicinity of the Fermi level can govern magnetic properties of LaFeAsO under fluorine doping and/or oxygen deficiency.

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Опубліковано

2010-01-28

Як цитувати

(1)
Fedorchenko, A.; Grechnev, G.; Desnenko, V.; Panfilov, A.; Volkova, O.; Vasiliev, A. Magnetic Properties and Electronic Structure of LaFeAsO0.85F0.1. Fiz. Nizk. Temp. 2010, 36, 292-298.

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