Jahn-Teller distortion, charge ordering, and magnetic transitions in Ca-doped NdMnO3

Structural and magnetic properties of (Nd1-xCax)MnO3, with x = 0, 0.38, and 0.55, have been investigated by means of neutron diffraction and ac magnetic susceptibility measurements. Ca doping induces a structural change to occur at around 250 K, that results in a much fatter unit cell and a significantly shorter axial Mn-O(1) bond length. Both antiferromagnetic and ferromagnetic behaviors were observed. Hole doping shifts the ordering temperature of the Mn spins to a much higher temperature and weakens the antiferromagnetic component as well. Reorientation of the Mn spins were also observed to occur at low temperatures for all three compounds studied.