Magnetic properties of exchange biased and of unbiased oxide/permalloy thin layers: a ferromagnetic resonance and Brillouin scattering study

TL;DR

This study compares the magnetic properties of permalloy thin layers interfaced with different oxides using ferromagnetic resonance and Brillouin scattering, revealing insights into anisotropy and interface effects.

Contribution

It provides a comparative analysis of magnetic parameters in permalloy layers with different interfaces using advanced spectroscopic techniques.

Findings

Perpendicular anisotropy is mainly due to interfacial surface energy.

Saturation magnetisation remains close to bulk values across thicknesses.

In-plane uniaxial and exchange-bias anisotropies are characterized.

Abstract

Microstrip ferromagnetic resonance and Brillouin scattering are used to provide a comparative determination of the magnetic parameters of thin permalloy layers interfaced with a non-magnetic (Al2O3) or with an antiferromagnetic oxide (NiO). It is shown that the perpendicular anisotropy is monitored by an interfacial surface energy term which is practically independent of the nature of the interface. In the investigated interval of thicknesses (5-25 nm) the saturation magnetisation does not significantly differ from the reported one in bulk permalloy. In-plane uniaxial anisotropy and exchange-bias anisotropy are also derived from this study of the dynamic magnetic excitations and compared to our independent evaluations using conventional magnetometry