Towards magnetic alumina: uncovering the roles of transition metal doping and electron hybridization in spin delocalization

J Phys Condens Matter. 2019 Jun 19;31(24):245801. doi: 10.1088/1361-648X/ab0fe4. Epub 2019 Mar 14.

Abstract

Judicious doping of normally diamagnetic alumina (Al2O3) could lead to bulk magnetism that would enable the usage of cutting edge technology, such as magnetoforming, to create advanced systems that take advantage of the high chemical and physical resilience of alumina. This study builds upon initial results (Nykwest et al 2018 J. Phys.: Condens. Matter 30 395801) which have shown that alumina doped with magnetic elements such as Fe and Ni should exhibit heightened magnetic activity. Here we expand the analysis to several additional transition metals that are otherwise non-magnetic (Sc, Ti, V, Mn, and Co) and use density functional theory to understand the origin of the spin delocalization, as well as to predict the structural, electronic, energetic, and magnetic properties of doped [Formula: see text]-alumina. The results indicate that adding small concentrations of such elements to [Formula: see text]-alumina may increase magnetic activity by generating coordination environments with magnetic moments. Our findings show conclusively that significant spin delocalization can only occur when there are unpaired electrons in the transition metal e g states.