Antisymmetric magnetoresistance of the ${\text{SrTiO}}_3/{\text{LaAlO}}_3$ interface

The longitudinal resistance $R_{xx}$ of the ${\text{SrTiO}}_3/{\text{LaAlO}}_3$ interface with magnetic fields applied perpendicular to the interface has an antisymmetric term [namely, $R_{xx}\left(H\right)\ne R_{xx}\left(-H\right)$] which increases with decreasing temperature and increasing field. We argue that the origin of this phenomenon is a nonhomogeneous Hall effect with clear contribution of an extraordinary Hall effect, suggesting the presence of nonuniform field-induced magnetization.

Figure 1

(Color online) (a) A sketch of the pattern. The width of the current path (between D and E) is $100\mu \text{m}$. The distance between neighboring Hall crosses is $300\mu \text{m}$. (b) The sheet resistance as a function of temperature. (c) The mobility as a function of temperature.

Figure 2

(Color online) $R^{AS}$ of the pairs [(a) and (c)] $b1-t1$ and [(b) and (d)] $b2-t2$ [(a) and (b)] as a function of a magnetic field applied perpendicular to the interface at different temperatures and [(c) and (d)] as a function of the angle $\theta$ between a field of 8 T and the normal to the interface at different temperatures. Open and full symbols are used for the bottom and upper sides of the current path, respectively.

Figure 3

(Color online) (a) The HE measurements as a function of a magnetic field on five different crosses of the same sample. Full and open symbols are used for temperatures of 2 and 60 K, respectively. (b) The HE after subtracting the assumed OHE extracted from the high field limit $\left(R_{xy}^{\ast }\right)$ for the same five crosses at 2 K. (c) The HE measurements as a function of $\text{cos}\theta$, where $\theta$ is the angle between a field of 8 T and the normal to the interface for the same five crosses at 60 K. (d) $R_{xy}^{\ast }$ as a function of the angle $\theta$ for the same five crosses at 2 K and a field of 8 T.

Figure 4

(Color online) The magnetoresistance as a function of $\theta$ with a field of 8 T at different temperatures (top) and at $T=2\text{K}$ with different fields (bottom).