Angular dependence of the Hall effect of La${}_{0.8}$Sr${}_{0.2}$MnO${}_3$ films

We find that the Hall effect resistivity (${\rho }_{xy}$) of thin films of La${}_{0.8}$Sr${}_{0.2}$MnO${}_3$ varies as a function of the angle $\theta$ between the applied magnetic field and the film normal as ${\rho }_{xy}=a\cos \theta +b\cos 3\theta$, where $\left|b\right|$ increases with increasing temperature and decreases with increasing magnetic field. We find that the angular dependence of the longitudinal resistivity and the magnetization cannot fully explain the surprising term $b$, suggesting it is a manifestation of an intrinsic transport property.

Figure 1

(a) Resistivity ($\rho$) as a function of temperature. Inset: Magnetoresistance, $\frac{R_0-R_H}{R_0}\times 100$, at ${\mu }_{0}H=8$ T, as a function of temperature. (b) Reduced magnetization as a function of temperature. (c) ${\rho }_{xy}$ as a function of magnetic field at different temperatures.

Figure 2

${\rho }_{xx}$ (top) and ${\rho }_{xy}$ (bottom) as a function of the external field angle $\theta$ at $T=125$ K (left) and $T=175$ K (right) for different fields. The lines are fits to Eqs. (1) and (3), respectively.

Figure 3

Top: $\Delta \rho /\rho$ as function of the temperature for different magnetic fields. Inset: Sketch of the relative orientations of the current density $J$, magnetic field $H$, magnetization $M$, and the crystallographic axes. The angle between $H$ and the film normal $\theta$ is rotating in the (010) plane. Bottom: The ratio between the AMR amplitude, $\Delta \rho /\rho$, at $H=4$ and $H=9$ T, as a function of temperature.

Figure 4

The fitting parameters from Eq. (3), (a) $a$ and (b) $b$, as a function of temperature for different magnetic fields. Inset: The field dependence of $a$ at $T=175$ K. The line is a linear fit. (c) The extracted $a_0$ (left) and $a_1$ (right) as function of temperature.

Figure 5

The extracted AHE resistivity $a_0$ as a function of the zero-field longitudinal resistivity.

Figure 6

Top: The ratio between the measured and calculated $b$, according to Eq. (4). Bottom: The difference between the measured and calculated $c_2$, according to Eq. (5), as a function of temperature.

Figure 7

$K_{\mathrm{anis}}/2M_s$ (top) and the ratio between the calculated and measured $K_{\mathrm{anis}}$ (bottom) as a function of temperature. Inset: The angular dependence of the longitudinal resistivity at ${\mu }_{0}H=1$ T and $T=5$ K. The solid line is a fit to Eq. (1), where $\alpha$ is calculated assuming $K_{\mathrm{anis}}/2M_s=0.8$ T.