A model for coupled $4f-3d$ magnetic spectra: a neutron scattering study of the Yb$-$Fe hybridisation in Yb${}_3$Fe${}_5$O${}_{12}$

Abstract

In this work, we explore experimentally and theoretically the spectrum of magnetic excitations of the Fe${}^{3+}$ and Yb${}^{3+}$ ions in ytterbium iron garnet (Yb${}_3$Fe${}_5$O${}_{12}$). We present a complete description of the crystal-field splitting of the $4f$ states of Yb${}^{3+}$, including the effect of the exchange field generated by the magnetically ordered Fe subsystem. We also consider a further effect of the Fe-Yb exchange interaction, which is to hybridise the Yb crystal field excitations with the Fe spin-wave modes at positions in the Brillouin zone where the two types of excitations cross. We present detailed measurements of these hybridised excitations, and propose a framework which can be used in the quantitative analysis of the coupled spectra in terms of the anisotropic $4f-3d$ exchange interaction.

References in corpus (2)

• Thermal spin dynamics of yttrium iron garnet
• Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures

Cited by in corpus (3)

• Understanding spin currents from magnon dispersion and polarization: Spin-Seebeck effect and neutron scattering study on Tb3Fe5O12
• Theory of the spin Seebeck effect influenced by crystal-field excitations in Tb${}_3$Fe${}_5$O${}_{12}$
• Origin and dynamics of umbrella states in rare-earth iron garnets