Magnons in the Multiferroic Phase of Cupric Oxide

Abstract

Polarized neutron scattering is used to characterize low-energy magnetic excitations in the multiferroic and antiferromagnetic phases of cupric oxide (CuO). The experiments are performed with the novel type of polarization analysis available at the thermal three-axes spectrometer PUMA@FRM, II allowing the simultaneous detection of spinflip and nonspinflip scattering. The energy gaps of several magnon modes are determined, and evidence for the existence of electromagnons near 3 and 13 meV is found.