Rf-sputtering deposition and magnetic characterisation of Nd-Fe-B thin films for microwave applications

The current trend towards integration in the telecommunication field leads us to study the magnetic layers. Nd-Fe-B films on Mo and Si(1 0 0) substrates, of the form of Mo/Nd-Fe-B, Si(1 0 0)/Nd-Fe-B, Si(1 0 0)/Ti/Nd-Fe-B and Si/Ti/Nd-Fe-B/Ti were prepared by magnetron sputtering. The effect of deposition parameters on the structure and the magnetic properties of the films has been studied. The hard Nd2Fe14B phase is formed by a postannealing treatment under argon only on the Si/Ti/NdFeB/Ti multilayers. The Ti underlayer prevents Fe-Si reactions and the Ti overlayer avoids Nd oxidation. No special crystallographic anisotropy is detected. The coercitive fields are about 480 kA/m. The presence of Nd2Fe14B phase is proved by low temperature magnetic measurements.