Abstracts 2003

Abstract of Publication No. 465

Stefan T. Ochsenbein, Grégory Chaboussant, Andreas Sieber, Hans U. Güdel, Stefan Janssen, Albert Furrer and J. Paul Attfield
Magnetic cluster excitations in the antiferromagnetic phase of a-MnMoO4
Phys. Rev. B 68, 092410/1-4 (2003)      Full Text (PDF)      DOI-Link     

Abstract: The tetramer-based compound a-MnMoO4 exhibits four prominent peaks in the inelastic neutron scattering (INS) spectrum between 0.5 and 2.0 meV below 10 K. They are assigned to magnetic excitations of the (Mn2+)4 rhombus shaped cluster, with resulting values of the exchange parameters J = +0.051 meV and J' = –0.019 meV along the edges and the short diagonal, respectively. The interactions within the tetramer are treated exactly in an isotropic quantum mechanical model leading to an S = 10 cluster ground state. The weaker antiferromagnetic (AFM) intercluster interactions, Jint = –4.5×10–3 meV, are treated in a molecular-field model below the AFM transition temperature TN = 10.7 K. INS and susceptibility are in quantitative agreement with this approach.

Last modified: 13.12.11 by Gabriela Frei