Magnetic ground states in Pr1-xSrxMnO3 (x=0.48-0.75)

The electric transport properties of single-crystal and ceramic samples of Pr1-xSrxMnO3 perovskites were investigated and correlated with structural a nd magnetic data. Analysis of the experimental data leads to the following conclusions: (i) the phase boundary between the ferromagnetic and A-type an tiferromagnetic ground states is observed at x = 0.49, (ii) the A-type syst ems are polaronic conductors in two dimensions, i.e., in the ferromagnetic planes, and approach the metallic conductivity with increasing x, (iii) an appreciable CMR effect in medium fields is observed for x similar to 0.50 d ue to the field-induced ferromagnetic transition, (iv) the A type-C type ph ase boundary occurs for x similar to 0.60, and, finally, (v) the charge car rier transport in the C-type antiferromagnets is reliably characterized by variable range hopping in one dimension i.e., along the ferromagnetic chain s. (C) 2001 American Institute of Physics.