Symmetry‐Controlled Sign Reversal and Anisotropy in Magnetoresistance of SrRuO3 Epitaxial Films

Understanding the magnetotransport properties of SrRuO3 thin films and heterostructures is essential for both fundamental research and practical applications. While the anomalous Hall effect has been studied extensively, the longitudinal magnetotransport (i.e. magnetoresistance) is not well understood and requires further investigation. Herein, SrRuO3/SrTiO3(001) epitaxial film is used as a model system to systematically investigate the correlation between magnetoresistance and structure symmetry. As the thickness of the SrRuO3 film increases, a structural symmetry transition from tetragonal to orthorhombic occurs. At the same time, a clear sign reversal of magnetoresistance from negative to positive, accompanied by the appearance of strong anisotropy in magnetoresistance measured along the two perpendicular in‐plane axes, is observed. These findings further suggest that the correlation between structural symmetry and magnetoresistance is mediated by the modulations in magnetic anisotropy. These results clarified the relationships between structure symmetry, magnetoresistance, and magnetic anisotropy, which can pave a feasible way for harnessing the magnetotransport properties of SrRuO3 films and using this material in oxide‐based spintronic devices. Sign reversal and anisotropy of magnetoresistance arising from a structural symmetry transition from tetragonal to orthorhombic are observed in SrRuO3 epitaxial films with various thicknesses, where uniaxial magnetic anisotropy is proved to be an essential connection. This thickness‐driven modulation of magnetoresistance can pave an essential approach for the magnetic signal read‐out in oxide‐based spintronic devices.