Exploring the Anomalous Nernst Effect in SrRuO$_3$

Abstract

We investigate the anomalous Nernst effect in epitaxial SrRuO$_3$ thin films grown on c-cut Al$_2$O$_3$ substrates, and in a polycrystalline SrRuO$_3$ slab. Through comprehensive measurements of the transverse thermoelectric response as a function of temperature and magnetic field, we observe a pronounced Nernst signal near $T_c$ in the (111) oriented SrRuO$_3$ thin films. The strong temperature and nontrivial field dependence underscore the pivotal role of the magnetic anisotropy in tuning the Berry curvature and, consequently, the anomalous Nernst effect in SrRuO$_3$.

Figures (4)

• Figure 1: Temperature-dependent resistivity and magnetization measured at an applied inplane magnetic field of 2kOe for (a) polycrystalline SRO slab, (b) SRO 800 nm thin film, and (c) SRO 10 nm thin film, showing distinct Zero-Field-Cooled (ZFC, black) and Field-Cooled (FC, dark green) magnetization curves, indicative of magnetic anisotropy.
• Figure 2: Temperature-dependent anomalous Nernst effect (ANE) measurements on (a) polycrystalline SRO slab, (b) SRO 800nm thin film and (c) SRO 10nm thin film. The ANE was measured under an applied magnetic field of 2kOe and a thermal gradient of 10K and the corresponding schematic of the measurement is illustrated in the inset. A pronounced Nernst signal near $T_c$ is observed in the (111)-oriented SRO thin films.
• Figure 3: Magnetic field-dependent-anomalous Nernst effect measurements on polycrystalline SRO slab along with SRO 800nm and SRO 10nm thin films grown on c-cut Al$_2$O$_3$ substrates, under a temperature gradient of 10K at various temperatures. A clear variation in loop area is observed, where the SRO 800nm and SRO 10nm thin films display pronounced broadening near $T_c$, whereas the polycrystalline sample shows a larger loop area at 55 K.
• Figure 4: Comparison of magnetic hysteresis loops and Field-dependent anomalous Nernst effect measured at 145K and 55K on SRO slab alongside SRO 800nm and SRO 10nm thin films on c-cut Al$_2$O$_3$ substrates, under an applied thermal gradient of 10K. At 55K, both SRO 800nm and SRO 10nm thin films exhibited a similar trend regardless of their magnetic hysteresis.