THE MANGANITE ND0.5SR0.5MNO3 - A RARE DISTORTION OF THE PEROVSKITE

The charge-ordered properties, characterized by a transition from an a ntiferromagnetic insulating to a ferromagnetic metallic state as tempe rature increases, have been evidenced for Nd0.5Sr0.5MnO3 with a transi tion temperature of 160K. The neutron diffraction and HREM study of th is manganite at room temperature shows that the space group of this or thorhombic structure (a=5.43 Angstrom,b=7.63 Angstrom, c=5.48 Angstrom ) is Imma. This new distortion of the perovskite structure is describe d and compared to that of the manganites with GdFeO3 type structure. T he quasi absence of Jahn Teller distortion of manganese in this phase is ascribed to its metallic properties at room temperature. Copyright (C) 1996 Elsevier Science Lid