Micro Magnetic Exchange Interaction Tensor and Magnetization Reversal of L1(0) FePt Based Alloy Thin Film Nano-Structures

作者：Singh Amritpal^*; Mryasov Oleg; Gupta Subhadra; Okatov Sergey; Gao Kaizhong; Girt Erol

来源：IEEE Transactions on Magnetics, 2013, 49(7): 3799-3801.

DOI：10.1109/TMAG.2013.2241404

• Exchange stiffness
• magnetic anisotropy
• magnetic hysteresis
• magnetic tunnel junction
• perpendicular magnetic recording

We investigate the effect of crystal symmetry driven tensor form of micromagnetic exchange stiffness A on switching properties of L1(0) FePt composite nano-structures. The exchange interaction term in micromagnetic energy functional have been constructed to capture the results of the first principle calculations for magnetic excitations in [001] and [100] directions. We find that out-of-plane (OP) exchange component (A(perpendicular to)) is about two times weaker as compared to the in-plane (IP) component (A(parallel to)). We study the effect of this difference between principal axis elements of A tensor on the M-H loops using micromagnetic simulations. We compare two cases for IP and OP exchange constants: (a) A(perpendicular to) = A(parallel to) (limited case) and (b) A(perpendicular to) = 0.5 A(parallel to) (based on ab-initio calculations), and find that the athermal coercive force for 30 x 30 nm bi-layer rectangular dots differs for these two cases. Further, we find that the coercive force difference between two cases decreases as the external field goes from OP to IP.

• 出版日期2013-7