Neutron-scattering studies of magnetism in multiferroic HoMnO3 (invited).

Authors :: Vajk, O. P.
Kenzelmann, M.
Lynn, J. W.
Kim, S. B.
Cheong, S.-W.
Source :: Journal of Applied Physics; 4/15/2006, Vol. 99 Issue 8, p08E301, 6p, 1 Diagram, 6 Graphs
Publication Year :: 2006
Abstract: Hexagonal HoMnO<subscript>3</subscript> is a frustrated antiferromagnet (T<subscript>N</subscript>=72 K) ferroelectric (T<subscript>C</subscript>=875 K) with a rich magnetic phase diagram consisting of multiple temperature- and field-dependent phases. Previously observed anomalies in the dielectric constant at magnetic phase transitions indicate strong coupling between the ferroelectricity and magnetism. Neutron-diffraction measurements in a magnetic field reveal new intermediate-field phases at low temperatures. Inelastic neutron-scattering measurements are used to establish the primary magnetic interactions and demonstrate that the spin dynamics in HoMnO<subscript>3</subscript> are well described by a simple two-dimensional nearest-neighbor Heisenberg antiferromagnetic exchange J=2.44 meV and a temperature-dependent anisotropy D. [ABSTRACT FROM AUTHOR]