Multicritical phase diagram of the electronic states in Sm1-x Srx Mn O3 (0.3

Abstract

For Sm1-x Srx Mn O3 (0.3 <0.5 changes to the layered (A -type) antiferromagnetic nonmetal at x>0.5. At x∼0.5 furthermore, where both TC and TN become comparable, the charge or orbital ordering appears. At x=0.50, the crystal first undergoes the transition to the layered-antiferromagnetic state at ∼130 K and subsequently to the CE -type antiferromagnetic charge or orbital-ordered state at ∼80 K as temperature decreases. The coexisting correlations of the charge or orbital ordering, ferromagnetic and layered-antiferromagnetic orderings are observed to evolve toward the tricritical point from high temperature around x=0.5. The magnetic-field induced metal-insulator phenomena have also been studied for the x=0.49, 0.50, and 0.51 crystals, and we have demonstrated on the temperature versus magnetic-field plane the competing features among the charge or orbital-ordered insulator, the layered (A -type) antiferromagnetic nonmetal, and the ferromagnetic metal. © 2006 The American Physical Society.