Intertwining of Frustration with Magneto-Elastic Coupling in the Multiferroic LuMnO3...

Residual magnetic frustration in the multiferroic LuMnO3 may be key towards understanding magneto-elastic
coupling in hexagonal manganites. Critical magnetic scattering present well above the magnetic ordering temperature TN
persists below, as observed by inelastic neutron scattering. The magnetic fluctuations are confined in two dimensions
implied by the characteristic wavevector dependence of the magnetic structure factor that changes from symmetric to
asymmetric across TN. The low dimensionality of the magnetic structure is also evident in the temperature dependence of
the commensurate antiferromagnetic intensity which follows a mean field exponent of ¢ ³ 0.2.