The role of the rare earth in the lattice and magnetic coupling in multiferroic h-HoMnO3

Abstract

We used Raman scattering to study the lattice and magnetic excitations in the hexagonal HoMnO3 single crystals. The E2 phonon mode at 237 cm-1 is affected by the magnetic order. This mode is related to the displacement of Mn and O ions in a-b plane and modulates the Mn-O-Mn bond angles in a-b plane and the in-plane Mn-Mn superexchange interaction. The mode at 269 cm-1 associated to the displacement of the apical Ho3+ ions along the c direction presents an abrupt change of slope at TN showing that the role of the rare earth ions can not be neglected in the magnetic transition. We have identified magnon and crystal field excitations. The temperature dependence of the magnetic excitations has been compared to the Mn and Ho moment and indicates that the exchange interaction pattern between Mn and Ho atoms drives the uniaxial anisotropy gap above the Mn-spin-rotation transition.

References in corpus (4)

• Electric-field control of spin waves at room temperature in multiferroic BiFeO3
• Large magnetothermal conductivity of HoMnO_3 single crystals and its relation to the magnetic-field induced transitions of magnetic structure
• Lattice and spin excitations in multiferroic h-YbMnO3
• Probing ultrafast spin dynamics in the antiferromagnetic multiferroic HoMnO${}_3$ through a magnon resonance

Cited by in corpus (1)

• Enhancement of magnetodielectric coupling in 6H-perovskites Ba3RRu2O9 for heavier rare earth cations (R=Ho,Tb)