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Y3Fe5O12 (YIG) and BiY2Fe5O12 (Bi:YIG) films are epitaxially grown on a series of (111)-oriented garnets substrates using pulsed laser deposition. Structural and ferromagnetic resonance characterizations demonstrate the high epitaxial quality, extremely low magnetic loss, and coherent strain state in these films. Using these epitaxial films as model systems, we systematically investigate the evolutions of magnetic anisotropy (MA) with epitaxial strain and chemical doping. For both the YIG and Bi:YIG films, the compressive strain tend to align the magnetic moment in film plane, while the tensile strain can compete with the demagnetization effect and stabilize a perpendicular MA. We found that the strain induced lattice elongation/compression along the out-of-plane[111] axis is the key parameter that determines the MA. More importantly, the strain-induced tunability of MA can be enhanced significantly by Bi doping, and meanwhile, the ultra-low damping feature persists. We clarified that the cooperation between strain and chemical doping could realize an effective control of MA in garnet-type ferrites, which is essential for spintronic applications.

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.