Hysteresis of Finite Arrays of Magnetic nano Dots

TL;DR

This study investigates the hysteresis behavior of finite arrays of magnetic nano dots, revealing size-dependent scaling laws and the influence of field misalignment on magnetic properties.

Contribution

It provides new insights into how finite size and field misalignment affect hysteresis in nano dot arrays, including scaling laws for hysteresis loop area.

Findings

Hysteresis loop area scales as N^{-3/2} for odd N

Hysteresis loop area scales as N^{-2} for even N

Field misalignment influences the shape of hysteresis loops

Abstract

Hysteresis curves for finite arrays of $N\times N$ ferromagnetic nano dots subject to the dipole-dipole interaction are investigated for $N=2... 13$. Spin arrangements up to N=6 are presented, which indicate the onset of bulk-like behavior associated with odd (N=5) and even (N=6) systems. The effect of field misalignment on the hysteresis loops is also studied for $N=3... 6$. The area $A_N$ of the hysteresis loop is studied as a function of $N$. We find that $A_N-A_\infty$ approximately scales as $N^{-{3/2}}$ for $N$ odd and as $N^{-2}$ for $N$ even.