Haiqing Xie, Qiang Wang, Hai-Bin Xue, HuJun Jiao, J. -Q. Liang
We investigate theoretically the effects of intrinsic spin-relaxation on the spin-dependent transport through a single-molecule magnet (SMM) weakly coupled to ferromagnetic leads. The tunnel magnetoresistance (TMR) is obtained by means of the rate-equation approach including not only the sequential but also the cotunneling processes. It is shown that the TMR disappears almost under the fast spin-relaxation in the sequential regime while can vary from large positive to small negative values in the cotunneling regime. Moreover, when a magnetic field is applied along the easy axis of the SMM, a large negative TMR is obtained with the increase of the relaxation rate. Finally in the large-bias voltage limit where all transport channels are open, the TMR for the negative bias is slightly higher than its characteristic value in the sequential regime, but for the positive bias case it becomes a negative value due to the fast spin-relaxation.
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http://arxiv.org/abs/1304.6044
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