Re-entrant spin glass transition in LaNdyK0.04MnO3: Origin and effects on the colossal magnetoresistivity
Department of Materials Science, Uppsala University Box 534, SE-751 21 Uppsala, Sweden
Accepted: 18 September 2000
Magnetic, electric and structural properties of LaNdyK0.04MnO with have been studied experimentally. A disordered magnetic state is formed as La is substituted by Nd, reflecting the competition between ferromagnetic (FM) double exchange and antiferromagnetic superexchange interactions. Key structural parameters are identified and correlated with changes in magnetic and electric properties. By application of a large magnetic field, spin disorder scattering is removed, creating a new magnetoresistance peak at a temperature lower than the first near- peak. Time-dependent zero-field–cooled magnetisation measurements have been performed for y=0.4 around this temperature. A re-entrant spin glass (RSG) transition is evidenced, with low field ageing properties in both the RSG and FM phases, similar to those observed in archetypal spin glass materials.
PACS: 75.30.Vn – Colossal magnetoresistance / 75.50.Lk – Spin glasses and other random magnets
© EDP Sciences, 2000