Action of strong coupling on steplike magnetization and transport properties in phase-separated manganite

For phase-separated La0.275Pr0.35Ca0.375MnO3 manganite, a steplike charge-ordered antiferromagnetic-ferromagnetic transition was observed by field induction and accompanied by a sudden drop of resistivity. The results can be explained in terms of the spin reorientation in the antiferromagnetic (AFM) phase and simultaneous destruction of orbital ordering by a magnetic field. Combined with specific heat and magnetization measurements, the electronic state density at Fermi energy was greatly enhanced at 5 T, which shows the increase of carrier number due to delocalization effect, by analogy with the spin reorientation due to destruction of orbital ordering by magnetic field. The present results prove that the strong coupling among spin, charge, and orbital ordering would be the main cause of existing complex physical behavior at low temperature, which depends sensitively on the spin orientation of adjacent charge-ordered AFM domains and can be controlled by applied field. (c) 2005 Americian Institute of Physics.