Magnetization reversal properties and magnetostatic interactions of disk to rod-shaped FeNi layers separated by ultra-thin Cu layers

From fast magnetic memories with low-power consumption to recording media with high densities, realizing the magnetization reversal and interaction of magnetic layers would allow for manipulating the ultimate properties. Here, we use a pulsed electrochemical deposition technique in porous alumina templates (50 nm in pore diameter) to fabricate arrays of nanowires, consisting of FeNi layers (26-227 nm in thickness) with disk to rod-shaped morphologies separated by ultra-thin (3 nm) Cu layers. By acquiring hysteresis curves and first-order reversal curves (FORCs) of the multilayer nanowire arrays, we comprehensively investigate magnetization reversal properties and magnetostatic interactions of the layers at different field angles (0 degrees <= theta <= 90 degrees). These involve the extraction of several parameters, including hysteresis curve coercivity (H ( c ) ( Hyst )), FORC coercivity (H ( c ) ( FORC )), interaction field distribution width (Delta H ( u )), and irreversible fraction of magnetization (IF ( m )) as a function of theta. We find relatively constant and continuously decreasing trends of H ( c ) ( Hyst ) when 0 degrees <= theta <= 45 degrees, and 45 degrees theta <= 90 degrees, respectively. Meanwhile, angular dependence of H ( c ) ( FORC ) and IF ( m ) shows continuously increasing and decreasing trends, irrespective of the FeNi layer morphology. Our FORC results indicate the magnetization reversal properties of the FeNi/Cu nanowires are accompanied with vortex domain wall and single vortex modes, especially at high field angles. The rod-shaped layers also induce maximum Delta H ( u ) during the reversal process, owing to enhancements in both magnetizing and demagnetizing-type magnetostatic interactions.

Automated summary

By using pulsed electrochemical deposition, we fabricated FeNi/Cu nanowire arrays and investigated the angle-dependent magnetization reversal properties and magnetostatic interactions. The results show that the magnetization reversal is influenced by vortex domain wall and single vortex modes, exhibiting different trends at high field angles.