Manipulation of spin-flip in CoO: a first principles study.

Manipulation of spin-flip is important in spintronics applications. In this paper, we report a simple manipulation of three Co-3 d spin states in the CoO spinel. From first principles calculations, we demonstrate that the spin state of Co atoms at octahedral sites (Co) of the CoO spinel can be manipulated through tensile stains. The magnetic moment of the Co changes from the ground non-magnetic (0 µ) state to the intermediate-spin state (2 μ) and high-spin state (4 μ) 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-3 d electrons in CoO 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. [ABSTRACT FROM AUTHOR]