Aligned high anisotropy Pr(Fe,Co,Mo)12N film samples

Abstract

Highly aligned (002) textured sputtered films of Pr(Fe12−y−zCoyMoz)Nx, where y=0–2.5, and z=0.4–1.0 compounds have been successfully synthesized. Before nitriding, the films exhibited nonuniaxial soft magnetic properties with room temperature coercivities of 0.70 kOe. A profound change of magnetocrystalline anisotropy occurred on nitriding. X-ray diffraction traces showed that the ThMn12-type tetragonal structure was retained with a saturating increase in cell volume over the first 15 min of nitriding time at 750 K. The coercivity, however, reached a maximum for a nitriding time of 25 min at 750 K. Samples nitrided for times greater than ≊25 min were taken as fully nitrided with ≊1 N per ThMn12 formula unit. The samples slightly richer in Pr showed somewhat higher coercivity perpendicular to the film plane as compared to stochiometric Pr(Fe,Co,Mo)12N films. From high field measurements to 80 kOe, the maximum room temperature coercivity perpendicular to the film plane was 9.4 kOe, which rose to 22.0 kOe at 10 K. The 4πMs value at 80 kOe measured perpendicular to the film plane was 11.6±0.5 kG at 293 K, 12.5 kG at 10 K, for Pr1.04Fe10.36Co1.16Mo0.44N samples, and 10.5±0.5 kG at 293 K for Pr1.05Fe11.17Mo0.78N samples. After high field magnetization to 80 kOe, for measurements perpendicular to the film plane, the static energy product was 23.6 and 32.9 MG Oe at 293 and 10 K, respectively. The estimated anisotropy fields were 96 and 144 kOe at 293 and 10 K, respectively, for low cobalt film samples.