Crystal Field Excitations in Breathing Pyrochlore Antiferromagnet Ba3Yb2Zn5O11

TL;DR

This study uses inelastic neutron scattering to analyze crystal field excitations in the breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11, revealing its anisotropic magnetic properties and confirming its pseudospin S=1/2 ground state.

Contribution

It provides the first detailed characterization of the crystal electric field levels and anisotropy in Ba3Yb2Zn5O11, establishing it as an experimental realization of a breathing pyrochlore antiferromagnet with easy-plane anisotropy.

Findings

Dispersionless excitations explained by CEF Hamiltonian.

Ground state exhibits planar-type anisotropy.

Magnetic susceptibility consistent with CEF energy scheme.

Abstract

Inelastic neutron scattering measurement is performed on a breathing pyrochlore antiferromagnet Ba3Yb2Zn5O11. The observed dispersionless excitations are explained by a crystalline electric field (CEF) Hamiltonian of Kramers ion Yb3+ of which the local symmetry exhibits C3v point group symmetry. The magnetic susceptibility previously reported is consistently reproduced by the energy scheme of the CEF excitations. The obtained wave functions of the ground state Kramers doublet exhibit the planer-type anisotropy. The result demonstrates that Ba3Yb2Zn5O11 is an experimental realization of breathing pyrochlore antiferromagnet with a pseudospin S = 1/2 having easy-plane anisotropy.