RESUMEN
To incorporate spintronics functionalities into two-dimensional devices, it is strongly desired to get two-dimensional electron gases (2DEGs) with high spin polarization. Unfortunately, the magnetic characteristics of the typical 2DEG at the LaAlO3/SrTiO3 interface are very weak due to the nonmagnetic character of SrTiO3 and LaAlO3. While most of the previous works focused on perovskite oxides, here, we extended the exploration for magnetic 2DEG beyond the scope of perovskite combinations, composing 2DEG with SrTiO3 and NaCl-structured EuO that owns a large saturation magnetization and a fairly high Curie temperature. We obtained the 2DEGs that show long-range magnetic order and thus unusual behaviors marked by isotropic butterfly shaped magnetoresistance and remarkable anomalous Hall effect. We found evidence for the presence of more conductive domain walls than elsewhere in the oxide layer where the 2DEG resides. More than that, a relation between interfacial magnetism and carrier density is established. On this basis, the intermediate magnetic states between short-range and long-range ordered states can be achieved. The present work provides guidance for the design of high-performance magnetic 2DEGs.
RESUMEN
180° domain wall motion in a tetragonal ferroelectric oxide is accelerated by an order of magnitude using in situ strain in a force microscope. Single-domain PbZr0.2 Ti0.8 O3 films on piezoelectric (001)-oriented 0.72PbMg1/3 Nb2/3 O3 -0.28PbTiO3 substrates allow for direct investigation of strain-dependent domain dynamics. The strain effect depends on the sign of applied field through strain-dependent electrode built-in potentials and a suggested charging of tilted walls.