Grain structure dependence of coercivity in thin films

TL;DR

This study uses finite element simulations to explore how grain size affects coercivity in nanocrystalline thin films, revealing the interplay of random and shape-induced anisotropies.

Contribution

It introduces a granular finite element model and extends the Random Anisotropy model to analyze coercivity dependence on grain size in thin films.

Findings

Coercivity varies with grain size in thin films.

Interplay of random and shape anisotropies influences magnetic behavior.

Simulation results align with extended anisotropy model.

Abstract

We investigated coercive fields of 200nm x 1200nm x 5nm rectangular nanocrystalline thin films as a function of grain size D using finite elements simulations. To this end, we created granular finite element models with grain sizes ranging from 5nm to 60nm, and performed micromagnetic hysteresis calculations along the y-axis (easy direction) as well as along the x-axis (hard direction). We then used an extended Random Anisotropy model to interpret the results and to illustrate the interplay of random anisotropy and shape induced anisotropy, which is coherent on a much larger scale, in thin films.