Phase diagram and anisotropic transport properties of Nd1-xSrxMnO3 crystals

We have investigated electronic transport and magnetic properties of perovskite-type Nd1-xSrxMnO3 crystals with change of controlled hole-doping level (0.30 less than or equal to x less than or equal to 0.80). The electronic phase diagram of Nd1-xSrxMnO3 was obtained by systematic measurements of magnetization (magnetic structure), resistivity, and lattice parameter. We have also studied the anisotropic transport properties of x=0.50 and 0.55 crystals with different magnetic structures: CE-type antiferromagnetic (AF) structure for x=0.50 and A-type layered AF one for x=0.55. In the case of the x=0.55 crystal, the metallic behavior was observed within the ferromagnetic (F) layers, while along the AF-coupling direction the crystal remains insulating over the whole temperature region. The observed large anisotropy is due to the magnetic as well as orbital-ordering induced confinement of the spin-polarized carriers within the F sheets. The nearly isotropic transport behavior has been confirmed for the CE-type AF charge-ordered state in the x=0.50 crystal.