Manipulation of spin-flip in Co3O4: a first principles study

Abstract

Manipulation of spin-flip is important in spintronics applications. In this paper, we report a simple manipulation of three Co-3d spin states in the Co3O4 spinel. From first principles calculations, we demonstrate that the spin state of Co atoms at octahedral sites (Cooct) of the Co3O4 spinel can be manipulated through tensile stains. The magnetic moment of the Cooct changes from the ground non-magnetic (0 µB) state to the intermediate-spin state (2 μB) and high-spin state (4 μB) when 5 % (or higher) uniaxial tensile strain and 3 % (or higher) biaxial tensile strain are applied to the lattice, respectively. Moreover, the mechanism of the spin state transition of the Co-3d electrons in Co3O4 is discussed, and we show that the occurrence of spin-flip is a result of the competition between the cubic crystal field energy and the exchange correlation energy. These results open a new route to achieve and manipulate triple-spin states in spintronic devices.