Regensburg 2019 – wissenschaftliches Programm
TT 35.6: Vortrag
Dienstag, 2. April 2019, 15:15–15:30, H23
Manipulating orbitals with magnetic fields — xionghua liu, •chun-fu chang, alexander komarek, steffen wirth, and liu hao tjeng — Max Planck Institute for Chemical Physics of Solids, Nöthnitzerstr. 40, 01187 Dresden, Germany
Magnetite (Fe3O4) is one of most controversially discussed materials in solid state physics due to its enigmatic Verwey transition, while being heavily studied as thin film for spintronic applications. Here, we report on our study of the Verwey transition under magnetic fields in Fe3O4 thin films on spinel substrates Co2−x−yMnxFeyTiO4 and non-magnetic Mg2TiO4. The Verwey transition of these films is highly tunable and anisotropic with applied magnetic fields. The strong magnetostriction evidences an active spin-orbit effect of the Fe2+ (d6) ions in Fe3O4 which allows one to manipulate the Fe2+ orbital occupation via magnetic fields. Remarkably, the high magnetic tunability of the Verwey transition results in a closed magnetoresistance (MR)-loop with an MR as large as 88% at 0.5 Tesla, which is up to 2 order larger than the reported values of Fe3O4 films.