Measurement of the crystalline anisotropy in sputtered single-crystal FeTaN thin films

Publisher Website
Google Scholar
Abstract
FeTaN single‐crystal thin films were grown in order to investigate the dependence of the crystalline anisotropy constant, K1, on the Ta and nitrogen content. Films with 5 and 10 wt % Ta and different nitrogen contents were prepared by dc sputtering on MgO(100) substrates at elevated temperatures. The film/substrate orientation was (100)∥(100) and [100]∥[110]. The values of K1 were determined by measuring the in‐plane angular dependence of the ferromagnetic resonance spectra and agreed very well with the values obtained from torque measurements, indicating that the total volume was biaxial cubic material. The hysteresis loops were characteristic of biaxial anisotropy and the anisotropy fields estimated from magnetization curves were consistent with the resonance and torque data. In Fe, K1 was (4.8±0.1)×105 ergs/cc in good agreement with the bulk value. In FeTa, K1 decreased to (4.4±0.1)×105 and (3.5±0.1)×105 ergs/cc for 5 and 10 wt % Ta content, respectively, and further to (2.7±0.1)×105 and (2.1±0.1)×105 ergs/cc in (Fe95Ta5)N depending on the nitrogen content. The nitrogen addition to Fe90Ta10 resulted in the formation of epitaxial (FeTa)4N which is an fcc structure with a negative K1 of (−1.5±0.2)×105 ergs/cc.