Magnetic Structure in Entropy Stabilized Single Crystal Spinel Ferrite Films*

“Entropy-stabilized oxides” possess large configurational entropy driven by the multi-cation disorder which dominates over the enthalpy of formation. The random distribution of constituent elements into the cation sublattice(s) enhances the configurational entropy. These oxide systems possess new possibilities for generating complex electronic and magnetic states due to the near degeneracies of cation spin-charge-orbital order parameters. Here, we grow single-crystal epitaxial thin films of extremely configurationally disordered spinel ferrites. We find that high entropy spinel oxide (HESO) films of (Mg_0.2Ni_0.2Fe_0.2Co_0.2Cu_0.2)Fe₂O₄ grown on various substrates—MgAl₂O₄ (MAO), MgO, and SrTiO₃ (STO)—demonstrate an interesting array of magnetic properties in terms of long-range stripe domains, strain-controlled magnetic anisotropy, unusual element-specific magnetization, and magnetic phase transition well above room temperature. The extreme number of cations and configurational degeneracy is expected to open many new avenues for fundamental physics and applied works.