Title :
Effects of La3+ substitution on the magnetic properties of double perovskites A2FeMoO6 (A=Ca and Ba)
Author :
Han, H. ; Yang, H.M. ; Lee, W.Y. ; Kim, S.B. ; Kim, C.S. ; Lee, B.W.
Author_Institution :
Dept. of Phys., Hankuk Univ. of Foreign Studies, Kyungki, South Korea
Abstract :
We have studied effects of the partial substitution of La3+ for A2+ on the magnetic properties of double perovskites A2FeMoO6 (A=Ca and Ba). Polycrystalline A2-xLaxFeMoO6 (0≤x≤0.3) samples have been prepared by the conventional solid-state reaction in a stream of 5% H2/Ar gas. The X-ray data indicate that A=Ca is monoclinic with the space group P21/n and A=Ba is cubic with the space group Fm3m. The substitution of La3+ for A2+ results in a cell volume increase for A=Ca and a cell volume reduction for A=Ba. Saturation magnetization, which is 3.5 μB/f.u. for undoped A=Ca (x=0) and 3.9 μB/f.u. for undoped A=Ba (x=0), decreases with increasing x. This decrease of magnetization arises from the reduction of moment associated with the electron doping and the disorder at the Fe and Mo sites. The partial substitution of La3+ for Ba2+ considerably enhances the Curie temperature Tc from 316 K for x=0 to 334 K for x=0.2. However, the Tc in Ca2-xLaxFeMoO6 is not enhanced significantly with increasing x.
Keywords :
Curie temperature; X-ray diffraction; barium compounds; calcium compounds; crystal structure; ferromagnetic materials; iron compounds; lanthanum compounds; magnetic moments; magnetisation; 316 K; 334 K; A2FeMoO6; Ba2-xLaxFeMoO6; Ca2-xLaxFeMoO6; Curie temperature; La3+ substitution; cell volume; cubic space group; double perovskites; electron doping; magnetic properties; moment; monoclinic space group; partial substitution; polycrystalline samples; saturation magnetization; solid-state reaction; Argon; Doping; Electrons; Magnetic properties; Physics; Powders; Saturation magnetization; Solid state circuits; Temperature; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2003.816022