Magnetic properties of the Nd0.9MnOx cation-deficient manganites

This paper reports on the results of x-ray diffraction and magnetic studies of manganites in the Nd0.9MnOx system with an oxygen content varying in the range 2.84 < x < 2.93. A sample with an oxygen content x = 2.84 undergoes a first-order phase transition at a temperature close to T = 1050 K, whereas an anomaly observed in the elastic properties for a sample with x = 2.93 indicates a phase transition near T approximate to 500 K. It is assumed that these transitions are governed by cooperative ordering of Mn e (g) orbitals of the same type as in stoichiometric NdMnO3. The manganite at an oxygen content x = 2.85 is an antiferromagnet with a Neel temperature T-N = 85 K, whereas the magnetic properties of the manganites at x = 2.90 and 2.93 suggest that an antiferromagnetic component coexists with a ferromagnetic component. The magnetic interaction between the ferromagnetic and antiferromagnetic components manifests itself in the fact that the magnetic moment becomes opposite in direction to the external magnetic field. The properties of the samples are consistent with the hypothesis that part of the neodymium ions (up to 5%) can be substituted for manganese ions.