Spontaneous exchange bias and large dielectric constant in Bi0.8Tb0.2Fe0.8Mn0.2O3 multiferroic

Abstract

The structural, dielectric, and magnetic properties of Bi0.8Tb0.2Fe0.8Mn0.2O3 have been studied in detail. A structural shift from rhombohedral (space group R3c) to orthorhombic (space group Pn21a + Pnma) phase is observed with doping. The substitution of Mn and Tb gives a very large value of the dielectric constant. It has been demonstrated that the observed spontaneous exchange bias is larger than the conventional exchange bias at room temperature. Moreover, doping reduces the Neel temperature from 643 to 521 K and magnetization increases. Thermoremanent magnetization studies at room temperature show that the system is composed of an interfacial layer of an antiferromagnetic core and a two-dimensional diluted antiferromagnet shell with a net magnetization under the field. Furthermore, the system's reasonable HEB and HC values at room temperature make it intriguing and appealing for a variety of multifunctional devices.