Materials for permanent magnets

Permanent magnets play a pivotal role in many technological applications ranging from consumer electronic devices to electric power production and conversion. In particular, there is a huge interest for magnets containing cheap and abundant elements with small amounts of rare-earth elements. An interesting candidate in this respect is the chemically-ordered L10 phase of Fe50Ni50 (tetrataenite), which has been first found in iron meteorites. Unfortunately, the laboratory synthesis of the ordered phase is extremely challenging and several attempts have been made to achieve a high degree of chemical order in this alloy. Therefore, it is important to know how deviations from perfect chemical order affect magnetic properties.

Using first-principles-based density-functional theory calculations in combination with Monte Carlo (MC) simulations, we investigate the interplay between chemical order and the magnetic properties of tetrataenite. Our results indicate that the magneto-crystalline anisotropy in tetrataenite is rather robust against a certain degree of disorder.