Correlation of exchange-bias effect with negative magnetization in perovskite compound, La0.5Pr0.5CrO3

Abstract

Detailed investigations of the negative magnetization (NM) phenomenon and associated exchange bias (EB) effect in a single phase perovskite compound, La0.5Pr0.5CrO3, have been carried out. DC magnetization measurement under 200 Oe reveals a magnetic ordering (TN) at 264 K and a magnetization compensation at temperature, TCOMP ∼ 160 K. The compound exhibits NM as well as EB below TCOMP. The temperature and cooling field dependencies of EB have been investigated to reveal the dominant antiferromagnetic (AFM) and ferromagnetic (FM) interactions in La0.5Pr0.5CrO3. Both positive horizontal (HEB) and negative vertical (MEB) shifts (with respect to the origin) of field-cooled hysteresis curves are observed. Interestingly, both magnetization and EB (HEB and MEB) become zero at TCOMP. In addition, the EB (HEB and MEB) effect is maximum for a cooling field of 5 kOe, which is also the maximum field for observing NM behavior in La0.5Pr0.5CrO3, indicating a correlation between EB and NM. Rietveld refined neutron diffraction patterns at various temperatures infer a Gy type AFM ordering of Cr3+ moments below TN. Both NM and positive EB phenomena have been explained by considering the AFM exchange interaction between an induced moment of Pr3+ and a FM component of canted Cr3+ moment. The understanding is significant as it may open up the possibility for making thermomagnetic switches, magnetic memory, and other spintronic devices.