Tuning magnetic anisotropy energy in a Fe/Pt multilayered nanowire*

Magnetic anisotropy energy (MAE) arises from the directional dependent magnetic behavior of the materials. Magnetic data storage requires the MAE to be higher than k_BT (k_B is the Boltzmann constant and T is the room temperature) so that unintentional magnetization switching can be averted. Considerable efforts are made in recent years to find low dimensional materials with tunable MAE for their potential application in ultra-high density data storage device. Though spin-orbit coupling happens to be the prime cause, it is found that the dimensionality and symmetry also plays a key role in the enhancement of MAE with the recent findings that show the low symmetry nanoscale structures possess much larger MAE than the high symmetry bulk materials. Herein, using a periodic density functional approach that includes spin-orbit interaction, we have investigated the MAE in Fe/Pt multilayered nanowire; the role of Pt spacer in tuning MAE is examined. Based on our calculation, we predict an increase of an order of magnitude in MAE with the decrease of the Pt spacer layer thickness. By decreasing the number of Pt spacer layers from eight to seven in the nanowire supercell, the MAE is found to increase from 2.9 meV to 21 meV.
*The Computations are performed at Superior, the HPC cluster at MTU.