Speaker
Dr
Yunzhong Chen
(DTU Energy)
Description
The recent discovery of metallic conduction at the interface between two nonmagnetic (NM) oxide insulators1,2, such as LaAlO3 (LAO) or Gamma-Al2O3 epitaxially grown on SrTiO3 (STO), provides a new opportunity for post-silicon electronics. In particular, the oxide interfaces could be also ferromagnetic (FM). However, direct imaging using a scanning SQUID probe found that the magnetism at LAO/STO was inhomogeneous3, which in nature are micrometer-sized ferromagnetic patches in the plane parallel to the interface. It was also concluded that the ferromagnetism did not require mobile electrons, i.e. the 2DEG at LAO/STO is NM (mainly paramagnetic). Herein, I will present our study on making the NM oxide 2DEG FM. Specifically, we emulated the proximity-induced magnetism in magnetic semiconductors by combining the 3d oxide 2DEG with FM oxides. This results in the observation of anomalous Hall effect (AHE) that probes directly the ferromagnetism of the conducting electrons. The tunable phase diagram of the LAO/STO interface as well as the consistence of ferromagnetic 2DEG and interface superconductivity will be also presented4.
Reference:
1.A. Ohtomo & H. Y. Hwang, A high-mobility electron gas at the LaAlO3/SrTiO3 heterointerface. Nature 427, 423 (2004)
2.Y. Z. Chen et al. A high-mobility two-dimensional electron gas at the spinel/perovskite interface of γ-Al2O3/SrTiO3. Nature Commun. 4, 1371 (2013)
3.J. A. Bert et al. Direct imaging of the coexistence of ferromagnetism and superconductivity at the LaAlO3/SrTiO3 interface. Nature Phys. 7, 767-771 (2011)
4.Y. L. Gan, Y. Z. Chen et al. (unpublished).
Primary author
Dr
Yunzhong Chen
(DTU Energy)
