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.