High anisotropy Nd(Fe,T)12Nx, T=Ti, Mo, films and disordered RE(Fe,Ti) phases before and after nitriding

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Abstract
Highly textured thin films, of ordered Nd(Fe,T)12, T=Ti, Mo, and disordered Nd(Fe,Ti)7 phases, were synthesized by rf sputter deposition. The 1–12 films were highly (002) textured with the c axes oriented perpendicular to the film plane. The disordered Nd‐Fe‐Ti films were fitted to the disordered TbCu7 phase and could be made highly (110) textured with the c axes randomly distributed in the film plane. Nitriding was carried out in N2 at P=400 Torr at ≊450 °C for 2 h. The room‐temperature magnetocrystalline anisotropy fields of the NdFe11Ti and NdFe11Mo films, which were uniaxial, were 10 and 5 kOe, respectively. After nitriding the NdFe11TNx films remained uniaxial, but the anistropy fields increased to 108 and 130 kOe for Ti and Mo, respectively. The iHc perpendicular to the film plane of NdFe11T increased to 5.3 kOe, T=Ti, and to 7.2 kOe, T=Mo, after nitriding. At 293 K, the highest‐energy product of 30.2 MGOe was obtained for a T=Mo nitrided sample. The hysteresis loops of disordered Nd(Fe,Ti)7 and Nd(Fe,Ti)7Nx films, measured in the film plane and perpendicular to the film plane, showed that the disordered 1–7 phase was a conical system and that the cone angle increased after nitriding. Thin films of the disordered 1–7 phase were also synthesized with Nd replaced by Sm and these directly crystallized disordered Sm(Fe,Ti)7 films were highly (200) textured with the c axes randomly distributed in the film plane. As observed for the disordered Nd(Fe,Ti)7 phase, hysteresis loops of disordered Sm(Fe,Ti)7 and Sm(Fe,Ti)7Nx showed a change in cone angle after nitriding and, in this case, the cone angle decreased.