Magnetic hysteresis mechanism in Lu0.9Sr0.1Cr0.5Fe0.5O3 studied by Monte Carlo simulations.

In this work we report magnetic properties of the orthorhombic perovskite Lu0.9Sr0.1Cr0.5Fe0.5O3 synthesized by a wet chemical method. As in LuCr0.5Fe0.5O3 the compound with Sr shows the magnetization reversal phenomenon, but the magnetic order and the compensation temperature occur at higher temperatures. Interestingly, in M vs H curves a hysteresis loop is observed when Cr4+ and Cr3+ ions coexist as a consequence of the aliovalent substitution of Lu3+ by Sr2+ in the B sites of the perovskite. To explain this behavior, we performed numerical simulations with a magnetic model for Lu1-xSrxCr0.5Fe0.5O3 perovskites with x=0 and x=0.1. We found that the ferromagnetic coupling of Fe3+ and Cr4+ through superexchange interactions (according the empiric Goodenough-Kanamori-Anderson rules, GKA) increases the magnetization at high fields and that the presence of ferromagnetic clusters explains the hysteretic behavior found in simulations.