Simple Realistic Model of Spin Reorientation in 4f-3d Compounds

TL;DR

This paper presents a simple microscopic model explaining spin reorientation in 4f-3d compounds, highlighting the competition between anisotropies, crystal field effects, and 4f-3d interactions as the key factors.

Contribution

It introduces a realistic microscopic theory for spin reorientation transitions driven by 4f-3d interactions in rare-earth compounds.

Findings

Spin reorientation caused by 4f-3d interaction.

Temperature dependence explained by anisotropy competition.

Model aligns with observed phenomena in rare-earth perovskites.

Abstract

Spin reorientation is an important phenomenon of rare-earth perovskites, orthoferrites and orthochromites. In this study, we consider a simple but realistic microscopic theory of the spontaneous spin-reorientation transitions induced by the 4f-3d interaction, more specifically, the interaction of the main Kramers doublet or non-Kramers quasi-doublet of the 4f ion with an effective magnetic field induced by the 3d sublattice. The obtained results indicate that the cause of both the temperature and the character of the spin-reorientation transition is a competition between the second and fourth order spin anisotropy of the 3d sublattice, the crystal field for 4f ions, and the 4f-3d interaction.