Magnetic properties of Nd-Fe-B thick-film magnets prepared by laser ablation technique

Nd-Fe-B film magnets were prepared by a laser ablation technique. The suppression of oxidation is a key point to obtain Nd-Fe-B film magnets with high coercivity. The following methods were used. 1) Ta substrates and a Ti sublimation pump as an auxiliary pump were used during deposition. 2) The composition of a target was set to Nd_2.6Fe₁₄B which included a larger amount of Nd compared with the stoichiometric composition of Nd₂Fe₁₄B. In addition, the distance between a target and a substrate was approximately 5 mm to ensure a high deposition rate. One-hour deposition using laser ablation technique enabled us to obtain Nd-Fe-B amorphous films with the thickness of approximately 50 μm. After annealing the films under an optimum condition, the coercivity and the remanence were more than 800 kA/m and approximately 0.6 T, respectively. In addition, the maximum energy product was 56 kJ/m³.