Weak ferromagnetism and magnetization reversal in YFe_1−xCr_xO₃

¹ Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur P.O., Bangalore 560 064, India
² Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Jakkur P.O., Bangalore 560 064, India

^(a) sundaresan@jncasr.ac.in
^(b) raja@jncasr.ac.in

Received: 13 March 2012
Accepted: 11 June 2012

Abstract

We present combined experimental and theoretical studies on the magnetic properties of a solid solution between yttrium orthoferrite and yttrium orthochromite systems, YFe_1−xCr_xO₃ (0 ⩽ x ⩽1), where Fe³⁺ and Cr³⁺ ions are distributed randomly at the same crystallographic site (4b). We found that all the compositions exhibit weak ferromagnetism below the Néel temperature that decreases nonlinearly with increasing x, while certain intermediate compositions (x = 0.4,0.5) show a compensation point and magnetization reversal. This unusual behavior is explained based on a simple model comprising the isotropic superexchange and the antisymmetric Dzyaloshinskii-Moriya interactions. This model explains the magnetization behavior in the entire range of doping and temperature including the magnetization reversal which results from an interplay of various DM interactions such as, Fe-O-Fe, Cr-O-Cr and Fe-O-Cr.