Comparisons of the high- and low-field magnetic anisotropies in a single-crystal manganite and a polycrystalline cobaltite

¹ Department of Physics and Astronomy, University of Manitoba Winnipeg, MB R3T 2N2, Canada
² Moscow State Steel and Alloys Institute - Lenin Prosp. 4, Moscow 119991, Russia

Received: 10 May 2005
Accepted: 4 October 2005

Abstract

The approach to magnetic saturation has been used to estimate the magnetic anisotropy in single-crystal La_0.73Ba_0.27MnO₃ and polycrystalline La_0.5Sr_0.5CoO₃, and these estimates are compared with those found from the measured coercive field. While this analysis confirms the order-of-magnitude discrepancy between these two estimates reported previously and linked, via the enhanced anisotropic magnetostrictive behaviour, to a field-induced low- to high-spin state transition of the Co ion, it also indicates that such discrepancies may be a ubiquitous feature of these transition metal oxides, occurring in systems where orbital instabilities appear unlikely.