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Abstract Exchange bias (EB), manifested as a hysteresis‐loop offset after field‐cooling, is demonstrated in perovskite‐structured ferromagnet/antiferromagnet (La_0.67Sr_0.33MnO₃/YFeO₃)_nheterostructures grown on (100) SrTiO₃substrates. Bilayer samples show an EB of 306 Oe at 50 K, whereas multilayers with five layers exhibit an exchange bias of up to 424 Oe at 50 K. A spin valve consisting of La_0.67Sr_0.33MnO₃/SrTiO₃/La_0.67Sr_0.33MnO₃/YFeO₃shows stable remanent configurations resulting from pinning of the upper La_0.67Sr_0.33MnO₃layer by the YFeO₃. In contrast, EB is not observed on (111)‐oriented SrTiO₃substrates due to interface roughening. These results demonstrate YFeO₃as an alternative orthoferrite antiferromagnet compared to BiFeO₃and LaFeO₃for incorporation into exchange‐biased heterostructures. 

Abstract Complex oxides offer rich magnetic and electronic behavior intimately tied to the composition and arrangement of cations within the structure. Rare earth iron garnet films exhibit an anisotropy along the growth direction which has long been theorized to originate from the ordering of different cations on the same crystallographic site. Here, we directly demonstrate the three-dimensional ordering of rare earth ions in pulsed laser deposited (Eu_xTm_1-x)₃Fe₅O₁₂garnet thin films using both atomically-resolved elemental mapping to visualize cation ordering and X-ray diffraction to detect the resulting order superlattice reflection. We quantify the resulting ordering-induced ‘magnetotaxial’ anisotropy as a function of Eu:Tm ratio using transport measurements, showing an overwhelmingly dominant contribution from magnetotaxial anisotropy that reaches 30 kJ m⁻³for garnets with x = 0.5. Control of cation ordering on inequivalent sites provides a strategy to control matter on the atomic level and to engineer the magnetic properties of complex oxides.