Influence of the heat treatment on magnetization reversal of orthorhombic perovskites LaFe0.5Cr0.5O3

In this work, we show the influence of the thermal treatment on the reverse magnetization of the LaFe0.5Cr0.5O3 compound. The bulk samples were prepared by the combustion method using urea as fuel. After combustion, the dry powder was thermally treated at 1000 °C and 1300 °C for 24 h. Structural properties of this samples were analyzed by X-ray diffraction followed by Rietveld refinement. This study reveals that both samples are monophasic with orthorhombic structure (Pbnm). The magnetic properties were investigated by measurement of the magnetization as a function of temperature and magnetic field carried out on a SQUID magnetometer MPMS-7T by Quantum Design. The measure of the magnetization as a function of temperature with an external magnetic field of 100 Oe reveals that the phenomenon of reverse magnetization (MR) is present only in sample thermally treated at 1300 °C. The hysteresis loop in 5 K shows a characteristic magnetic irreversibility of compounds with weak ferromagnetic behavior. The weak ferromagnetism in this compound can be attributed to the canting of the antiferromagnetically ordered spins due to the presence of a Dzyaloshinskii–Moriya interaction. The sample thermally treated at 1300 °C shows a discrete increase of the magnetization in 7 T.