Regensburg 2019 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 24: Spintronics (joint session TT/DY/MA)

DY 24.6: Talk

Tuesday, April 2, 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 Co_2−x−yMn_xFe_yTiO₄ 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.