Coupled Spin Waves And Crystalline Electric Field Levels In Candidate Multiferroic Erfeo3

We report an inelastic neutron scattering study of candidate multiferroic ErFeO3, a compound that has been previously reported to have three different magnetic states and undergoes signatures of Fe3+-Er3+ cooperative coupling. The spectrum at low energy transfer is dominated by excitations of the Er3+ character, even above the Er3+ antiferromagnetic ordering temperature of 4.5 K. In addition, a crystalline electric field excitation at 6 meV exhibits additional energy splitting upon cooling through 4.5 K with mode-dependent polarization. This indicates different moment directions for these modes, an interesting consequence of C-y ordering of the Er3+ moments. Published under an exclusive license by AIP Publishing.