Large exchange bias effect and complex magnetism in a tetragonal high entropy spinel oxide

Abstract

In this study, we have employed a high entropy approach to synthesize a hitherto unexplored tetragonal high entropy spinel with composition (Mn0.2Co0.2Ni0.2Cu0.2Zn0.2)Mn1.8Cr0.2O4. The temperature and field-dependent magnetization studies reveal a complex magnetic behavior characterized by a ferrimagnetic transition occurring at (TC) 85 K, followed by a noncollinear magnetic ground state below 23 K. Remarkably, we have observed the appearance of a large exchange bias effect (exchange bias field HEB = 7.6 kOe at 4 K) below the TC = 85 K in the field cooled mode. The uncompensated magnetic moments in this disordered system create unidirectional anisotropy, leading to the exchange bias effect. The appearance of the large exchange bias effect in a complex high entropy oxide (HEO) indicates that disordered ferrimagnetic HEOs are a promising class to explore systems having potential applications in spintronics.