Evolution of magnetic and microstructural properties of thick sputtered NdFeB films with processing temperature

Arnaud Walther (1) , Kirill Khlopkov (2) , Oliver Gutfleisch (2) , Dominique Givord (3) , Nora Dempsey (3)

1 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information
2 IFW Dresden - Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden
3 NEEL - MNM - Micro et NanoMagnétisme

Ta (100 nm) / NdFeB (5 µm) / Ta (100 nm) films have been deposited onto Si substrates using triode sputtering (deposition rate ~ 18 µm/h). A 2-step procedure was used : deposition at temperatures up to 400°C followed by ex-situ annealing at higher temperatures. Post-deposition annealing temperatures above 650°C are needed to develop high values of coercivity. The duration of the annealing time is more critical in anisotropic samples deposited onto heated substrates than in isotropic samples deposited at lower temperatures. For a given set of annealing conditions (750°C/ 10'), high heating rates (≥ 2000°C / h ) favour high coercivity in both isotropic and anisotropic films. The shape and size of Nd2Fe14B grains depend strongly on the heating rate.

Mots clés: NdFeB thick films

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Arnaud Walther, Kirill Khlopkov, Oliver Gutfleisch, Dominique Givord, Nora Dempsey. Evolution of magnetic and microstructural properties of thick sputtered NdFeB films with processing temperature. Journal of Magnetism and Magnetic Materials, 2007, 316 (2), pp.174-176. ⟨10.1016/j.jmmm.2007.02.047⟩. ⟨hal-00139185⟩