Magnetic structure and local lattice distortion in giant negative thermal expansion material Mn3Cu1-xGexN

Abstract

Magnetic and local structures in an antiperovskite system, Mn 3Cu1-xGexN, with a giant negative thermal expansion have been studied by neutron powder diffraction measurement. We discuss (1) an importance of an averaged cubic crystal structure and a ΓG5g antiferromagnetic spin structure for the large magneto-volume effect (MVE) in this itinerant electron system, (2) an unique role of a local lattice distortion well described by the low temperature tetragonal structure of Mn3GeN for the broadening of MVE. © 2010 IOP Publishing Ltd.