Magnetocrystalline anisotropy and exchange probed by high-field anomalous Hall effect in fully-compensated half-metallic Mn2RuxGa thin films

TL;DR

This study investigates the magnetocrystalline anisotropy and exchange interactions in fully-compensated Mn2RuxGa thin films using high-field anomalous Hall effect measurements, revealing key magnetic properties and resonances.

Contribution

The paper introduces a detailed analysis of exchange constants and anisotropy in Mn2RuxGa, utilizing high-field magnetotransport and molecular field modeling, advancing understanding of ferrimagnetic half-metals.

Findings

Non-zero Hall signal across temperature range including compensation point

High anomalous Hall conductivity of 6673 Ω^{-1}.m^{-1}

Inferred anisotropy of 216 kJ/m^3 and predicted magnetic resonance frequencies

Abstract

Magnetotransport is investigated in thin films of the half-metallic ferrimagnet Mn$_2$Ru$_x$Ga in pulsed magnetic fields of up to 58 T. A non-vanishing Hall signal is observed over a broad temperature range, spanning the compensation temperature 155 K, where the net magnetic moment is strictly zero, the anomalous Hall conductivity is 6673 $\Omega^{-1}.m^{-1}$ and the coercivity exceeds 9 T. Molecular field modelling is used to determine the intra- and inter-sublattice exchange constants and from the spin-flop transition we infer the anisotropy of the electrically active sublattice to be 216 kJ/m$^3$ and predict the magnetic resonances frequencies. Exchange and anisotropy are comparable and hard-axis applied magnetic fields result in a tilting of the magnetic moments from their collinear ground state. Our analysis is applicable to collinear ferrimagnetic half-metal systems.