Direct evidence of phase segregation and magnetic-field-induced structural transition in Nd0.5Sr0.5MnO3 by neutron diffraction

We present direct evidence of die phase segregation and magnetic-field-induced structural transition in Nd0.5Sr0.5MnO3 as proposed earlier [R. Mahendiran et al., Phys. Rev. Lett. 82, 2191 (1999)] for the collapse of the charge-ordered insulating state. The spontaneous (H=0) low-temperature phase at 125 K is found to be phase segregated into two different crystallographic structures and three magnetic phases: orthorhombic (Imma) ferromagnetic, orthorhombic (Imma) A-type antiferromagnetic, and monoclinic (P2(1)/m) charge-ordered CE-type antiferromagnetic phases. Under a field of H=6 T, the charge-ordered monoclinic phase collapses and completely transforms into the metallic ferromagnetic orthorhombic phase.