Formation, structure and magnetic properties of Nd3−xZrxFe27.8Mo1.2 (0.1 ≤ x ≤ 0.5) compounds

Nd3−xZrxFe27.8Mo1.2 (0.1 ≤ x ≤ 0.5) compounds with monoclinic Nd3(Fe, Ti)29-type structure have been synthesized successfully and their structure and magnetic properties were investigated by powder X-ray diffraction, powder neutron diffraction and magnetic measurements. The highest Zr content in per formula of Nd3−xZrxFe27.8Mo1.2 compound is about 0.5 and higher Zr content will result in the transformation of phases from monoclinic Nd3(Fe, Ti)29-type structure to the rhombohedral Th2Zn17-type one. At x ≤ 0.5, both the reduction of the lattice parameters a, b, c and the unit-cell volumes V with increasing Zr content and the obtained Zr occupancies based on Rietveld refinement of XRD patterns indicate that Zr atoms prefer to substitute for rare earth (Nd) and enter into the 2a and 4i sites. With more Nd replaced by Zr, the magnetic properties, including the Curie temperatures and saturation magnetizations at room temperature, decrease monotonically.