Neutron Diffraction and Paramagnetic Scattering from a High Pressure Phase of MnGeO₃ (Ilmenite)

Abstract

The magnetic structure as well as the exchange parameters in MnGeO₃ with the ilmenite structure have been investigated by neutron diffraction and paramagnetic scattering using powder sample prepared at 1000°C under high pressure of 50 kbar. It has been found that the crystal has the same antiferromagnetic structure as MnTiO₃; the spins are directed along the [111] rhombohedral axis and are aligned in antiparallel in the layer. The nearest neighbor Mn²⁺ distance is 3.02Å and the exchange integral J₁ between them is found to be 0.84±0.01 meV.