Effects of neodymium doping on the structural and magnetic properties of the double perovskite Sr2-yNdyFe1+xMo1-xO6 compound

Curie temperature (T-C) of the ferromagnetic compound Sr2FeMoO6 can be modified by increasing the itinerant electrons at the Fermi level. Nd doping increases the electron density but the charge neutrality should be taken into account. In this work, a series of double perovskites Sr2-yNdyFe1+xMo1-xO6 (y = 0.0, 0.25, 0.5, 0.75 and 1.0) for both cases, the off-stoichiometric (x = 0) and the stoichiometric (x > 0 with x = y/2) one, were synthesized via solid state route and discussed in detail. A crystalline structure transition was confirmed by X-ray diffraction analysis, showing a change of the lattice parameters and the unit cell volume as a function of Nd doping. It was also found that the nominal valence in Fe is mainly Fe3+ and in Mo is Mo4+. The T-C increases continuously with Nd doping in the stoichiometric case. The increase of the T-C follows a competition with the substitution of Sr2+ ions by Nd3+ ions and the charge neutrality considered in our system.