Epitaxy of high-quality antiferromagnetic metal chromium nitride films with 90° and 40° off-axis magnetron sputtering

Chromium nitride (CrN), with its near room-temperature antiferromagnetic transition, is regarded as a promising candidate for next-generation spintronic devices. While epitaxial CrN films have been successfully synthesized via pulsed laser deposition, growing high-quality CrN films using magnetron sputtering (a widely applied technique for large-scale fabrication) remains a big challenge. In this work, we develop a method to synthesize high-quality epitaxial CrN films by a homemade 90° and 40° off-axis magnetron sputtering epitaxy. The residual resistivity ratio of these CrN films is around 3.28, one of the highest values in reports. Moreover, the effects of different sputtering setups (90° and 40° off-axis) on the physical properties of the CrN films were systematically investigated. It is shown that both CrN films have high crystallinity, superior conductivity (σ ∼ 6200 S/cm), and robust near room-temperature (TN ∼ 270 K) Néel transitions. Compared to the CrN films grown by the 40° off-axis sputtering, the CrN films synthesized by the 90° off-axis sputtering have higher Néel temperatures (276 K) and carrier mobility (77 cm2 V−1 s−1). Our work provides a way to synthesize high-quality CrN films by magnetron sputtering epitaxy and uncovers the effects of the off-axis sputtering geometry on the physical properties of films.