Magnetic properties of nickel electrodeposited on porous GaN substrates with infiltrated and laminated connectivity

TL;DR

This study investigates the magnetic properties of nickel deposited on porous GaN, demonstrating how porosity and nickel amount influence magnetization and low strain, with potential for magnetic-semiconductor applications.

Contribution

It presents a novel fabrication and analysis of nickel-infiltrated porous GaN structures, revealing their magnetic behavior and low strain characteristics.

Findings

Nickel-infiltrated porous GaN exhibits dominant magnetic properties from infiltrated material.

Magnetization varies from isotropic to shape-anisotropic with porosity and nickel amount.

Both structures show low strain and coercivity, indicating increased compliance of porous GaN.

Abstract

We studied the magnetic properties of ferromagnetic-semiconductor composites based on nickel and porous-GaN, motivated by the effort to couple magnetic and semiconductor functionality. Nickel-infiltrated and nickel-coated (laminated thin-film) porous GaN structures were fabricated by electrodeposition, and their magnetic properties were subsequently examined collectively, by vibrating sample magnetometry and on the nanoscale, by magnetic force microscopy. We successfully demonstrated the ability to realize nickel infiltrated porous GaN, where the magnetic properties were dominated by the infiltrated material without a measurable surface contribution. We found that the structure and magnetization of electrodeposited porous-GaN/Ni composites depended on GaN degree of porosity and the amount of deposited nickel. The magnetization evolves from a nearly isotropic response in the infiltrated structures, to a shape-anisotropy controlled magnetic thin-film behaviour. Furthermore, both infiltrated and thin-film nickel electrodeposited on porous GaN were found to have low (< 0.1%) strain and corresponding low coercivity: < 6.4 and < 2.4 kA/m for infiltrated and thin-film, correspondingly. The most likely cause for the lowered strain is increased compliance of the porous GaN compared to bulk. These results encourage deeper investigation of magnetic nanostructure property tuning and of magnetic property coupling to GaN and similar materials.