Structure and magnetic properties of sputtered Nd-Fe-B alloys
Studies were conducted on the relationship between the composition of Nd-Fe-B alloys, the temperature of the substrate, additional heat treatment and magnetic properties, crystalline phases, and microstructure and texture of films 30 to 300 μm thick produced by ion-plasma sputtering of cast targets. The sputtering rate was maintained at ~30 μm/h. The axial crystalline texture (001) along the normal to the sputtering plane is formed at a sputtering temperature within the limits ranging from 300 to 450 °C and higher than 600 °C. In the intermediate domain of sputtering temperatures, there is a deterioration of the texture (001), or such a change of the indices of the texture when the normal to one of the planes of the zone [010] becomes its axis. Within the framework of the classical theory of crystallization, a model of growth texture formation during the course of sputtering is suggested. The model explains the nonmonotonic change of texture with the change of sputtering temperature. The data obtained about the structure and properties of films have made it possible to optimize the sputtering process with a view to obtaining sputtered magnets with very good permanent magnet properties. Examples of magnetic systems and devices with sputtered magnets are given.
