Growth characteristics and magnetic properties of sputtered Nd-Fe-B thin films

Thin Nd-Fe-B films (200 to 2000 nm) with good hard magnetic properties have been produced bl magnetron sputtering in UHV. We have investigated the influence of substrate temperature and sputtering gas pressure on the structural and magnetic properties of the films. It was found that the composition of the films strongly depends on the argon pressure. This gives us the possibility to vary the Nd content in the range of 13 to 32 at%. Highly textured films can be produced at low gas pressure (0.03 mbar) and low substrate temperatures (approximate to 675 K). Thee films exhibit a low coercivity (100 to 300 kA/m) and low remanence, but have a high saturation polarization of about 1.5 T, measured vertical to the film plane. High coercive films (H-cj = 800-1200 kA/m) with a remanence of about 1.05 T can be achieved through sputtering at high argon pressures (0.1 to 0.2 mbar) and a substrate temperature in the range of 800 to 900 K.