MAGNETIC-PROPERTIES OF NDFEB THIN-FILMS ON PLATINUM UNDERLAYERS

A series of NdFeB (Nd12Fe82B6) films of different thicknesses were r.f . sputtered on 1000 Angstrom - thick Pt underlayers for information st orage application. The perpendicular coercivity has a maximum of 3000 Oe for a 1000 Angstrom - thick film annealed at 625 degrees C for fift een minutes. By using Transmission Electron Microscopy (TEM) we have f ound that the film is tetragonal with an additional fee structure. The crystallographic texture is established during annealing at 625 degre es C. The TEM micrographs show some voids and a grain size in the rang e 30 to 50 nm. For films annealed at 700 degrees C for fifteen minutes , the voids disappeared and the grain size was found to be 100 nm. X-R ay Diffraction analysis of the annealed sample indicates that the NdFe B film is amorphous.' Annealing at 625 degrees C produces the 2:15 :1 phase in the films.