Properties of the ferrimagnetic double-perovskite A₂FeReO₆ (A=Ba and Ca)

1999/04/08 by W. Prellier, V. Smolyaninova, Amlan Biswas +4 · 1 citation
Physics and Astronomy · #cond-mat.mtrl-sci #cond-mat.str-el

paper · pdf · doi:10.1088/0953-8984/12/6/318

5 pages REVTeX, 7 figures included, submitted to PRB

arxiv created 1999/04/08 · arxiv updated 2009/11/30

Abstract

Ceramics of A₂FeReO₆ double-perovskite have been prepared and studied for A=Ba and Ca. Ba₂FeReO₆ has a cubic structure (Fm3m) with a≈ 8.0854(1) Åwhereas Ca₂FeReO₆ has a distorted monoclinic symmetry with a≈ 5.396(1) Å, b≈ 5.522(1) Å, c≈ 7.688(2) Å and β=90.4^∘ (P21/n). The barium compound is metallic from 5 K to 385 K, i.e. no metal-insulator transition has been seen up to 385 K, and the calcium compound is semiconducting from 5 K to 385 K. Magnetization measurements show a ferrimagnetic behavior for both materials, with T_c=315 K for Ba₂FeReO₆ and above 385 K for Ca₂FeReO₆. A specific heat measurement on the barium compound gave an electron density of states at the Fermi level, N(E_F) equal to 6.1× 10²⁴ eV^-1mole^-1. At 5 K, we observed a negative magnetoresistance of 10 % in a magnetic field of 5 T, but only for Ba₂FeReO₆. Electrical, thermal and magnetic properties are discussed and compared to the analogous compounds Sr₂Fe(Mo,Re)O₆.

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