Spin wave dynamics of MnO confined in nanometer pores

The spin wave dynamics of MnO confined in a nanoporous matrix has been investigated by inelastic neutron scattering, using the direct geometry time of flight spectrometer MARI as the ISIS spallation source. Despite bulk measurements upon confined MnO indicating a 1K enhancement of T-N, our data show the vertical bar Q vertical bar dependence of the magnetic scattering in the confined system to be centered at around 0.9 angstrom (-1) as opposed to 1.5 angstrom (-1) in the bulk. This is an indication of a change in the length scale for the confined system. Furthermore, a large contribution to the magnetic scattering is observed below 10 meV in the confined system indicative of a range of exchange interactions present in the confined system. (c) 2006 Elsevier B. V. All rights reserved.