MRS Proceedings

Table of Contents - Volume  602  - Symposium JJ – Magnetoresistive Oxides & Related Materials  

Editors : M. Kawasaki, A.J. Millis, S.von Molnr, M. Rajeswari, M. Rzchowski

Articles

Properties of the Ferrimagnetic Double-Perovskites A2FeReO6 (A=Ba and Ca)

1999 MRS Fall Meeting.

W. Prelliera1a2 p1, V. Smolyaninovaa1, A. Biswasa1, C. Galleya1, R.L. Greenea1, K. Rameshaa3 and J. Gopalakrishnana3

a1 Center for Superconductivity Research and Department of Physics, University of Maryland, College Park, MD 20472, USA

a2 Current address: Laboratoire CRISMAT-ISMRA, CNRS UMR 6508, 6 Bd. du Maréchal Juin, 14050 Caen, France

a3 Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India

Abstract

We have synthesized ceramics of A2FeReO6 double-perovskites A2FeReO6 (A=Ba, Ca). Structural characterizations indicate a cubic structure with a=8.0854(1) Å for Ba2FeReO6 and a distorted monoclinic symmetry with a=5.396(1) Å, b=5.522(1) Å, c=7.688(2) Å and β=90.4° for Ca2FeReO6. The barium compound is metallic from 5K to 385K, i.e. no metal-insulator transition has been seen up to 385K, and the calcium compound is semiconducting from 5K to 385K. Magnetization measurements show a ferrimagnetic behavior for both materials, with Tc =315 K for Ba2FeReO6 and above 385K for Ca2FeReO6. At 5K we observed, only for Ba2FeReO6, a negative magnetoresistance of 10% in a magnetic field of 5T. Electrical, magnetic and thermal properties are discussed and compared to those of the analogous compounds Sr2Fe(Mo,Re)O6 recently studied.

Correspondence:

p1 Author to whom correspondence should be addressed: prellier@ismra.fr

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