Ferrimagnetic nanostructures for magnetic memory bits

TL;DR

This paper explores heat-assisted magnetic recording using ferrimagnetic DyCo$_5$ nanostructures with patterned antidot arrays, revealing temperature-dependent magnetic reorientation and domain formation, advancing potential high-density magnetic memory technology.

Contribution

It demonstrates the magnetic behavior of ferrimagnetic DyCo$_5$ antidot arrays near room temperature, highlighting their potential for improved magnetic storage devices.

Findings

Magnetization reorients from out-of-plane to in-plane above T$_R$.

Unexpected in-plane magnetic domains form below T$_R$ with ~45 nm modulation.

Patterned nanostructures show distinct magnetic properties compared to thin films.

Abstract

Increasing the magnetic data recording density requires reducing the size of the individual memory elements of a recording layer as well as employing magnetic materials with temperature-dependent functionalities. Therefore, it is predicted that the near future of magnetic data storage technology involves a combination of energy-assisted recording on nanometer-scale magnetic media. We present the potential of heat-assisted magnetic recording on a patterned sample; a ferrimagnetic alloy composed of a rare earth and a transition metal, DyCo$_5$, which is grown on a hexagonal-ordered nanohole array membrane. The magnetization of the antidot array sample is out-of-plane oriented at room temperature and rotates towards in-plane upon heating above its spin-reorientation temperature (T$_R$) of ~350 K, just above room temperature. Upon cooling back to room temperature (below T$_R$), we observe a well-defined and unexpected in-plane magnetic domain configuration modulating with ~45 nm. We discuss the underlying mechanisms giving rise to this behavior by comparing the magnetic properties of the patterned sample with the ones of its extended thin film counterpart. Our results pave the way for novel applications of ferrimagnetic antidot arrays of superior functionality in magnetic nano-devices near room temperature.