College Park, Maryland June 6 - 10 , 2004
WP63: Neutron Investigation of Low Temperature Magnetization Steps in CMR Manganites
F.M. Woodward, J.W. Lynn (NIST Center for Neutron Research), M.B. Stone, P. Schiffer (Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16082), D.N. Argyriou (Hahn-Meitner-Institut Berlin), L.C. Chapon (ISIS, Rutherford Appleton Laboratory), J.F. Mitchell (Materials Science Division, Argonne National Laboratory)
The doped manganite Pr0.7(CaxSr1-x)0.3MnO3 (x=0.0 0.7,0.75), shows anomalous steps in bulk magnetization and resistivity as a function of applied field for T<2 K, both in powdered and single crystal samples. Neutron diffraction was used as a probe to investigate the nature of these steps. Ferromagnetic and antiferromagnetic intensity as a function of field were measured in a single crystal sample at T=2 K. On increasing the field from the virgin state the antiferromagnetic phase abruptly disappears at H = 1.75 T, with a concomitant increase in the ferromagnetic intensity. Once the transition occurs, the system remains fixed in the new state when the field is returned to zero. Details of the magnetic and crystallographic structures as a function of field will be presented.
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