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The characteristics of the cooperative Mott-Peierls metal-insulator transition (MIT) of VO2 can be altered by employing epitaxial strain. While the most commonly used substrate for this purpose is isostructural rutile TiO2, thin films often suffer from interdiffusion of Ti ions near the interface. Exploiting this phenomena, we investigate the nature of interfacial V4+/Ti4+ cation intermixing and its effects on the MIT using scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS), soft x-ray absorption spectroscopy (XAS), and hard x-ray photoelectron spectroscopy (HAXPES), along with supporting density functional theory (DFT) calculations. We find that the reduced orbital occupancy in highly Ti incorporated VO2 is responsible for suppressing the MIT. Interdiffused films are found to be metallic at all measured temperatures, despite a resolute dimerization inferred from x-ray absorption data at lower temperatures. Our results demonstrate that the Mott physics can be suppressed in doped VO2, while a lattice dimerization remains thermodynamically favorable. [ABSTRACT FROM AUTHOR]

We report cryogenic magnetic force microscopy (MFM) studies of a 200-nm-thick hexagonal (h) LuFeO3 film grown by molecular-beam epitaxy on a (111)-oriented yttria-stabilized cubic-zirconia substrate. Labyrinthlike domains ~1.8μm in size were observed after zero-field cooling below the Néel temperature, TN≈147 K, where weak ferromagnetic order (P63cm) with a canted moment of MS≈0.02μB/f.u. exists. At 6 K, MFM images of the magnetization reversal process reveal a typical domain behavior of a pinning-dominated hard magnet. The pinning strength is substantially reduced at elevated temperature. The temperature dependence of the domain contrast demonstrates that our MFM is able to detect the domain contrast of magnets with tiny magnetic moments (~0.002μB/f.u.). An upper limit of the linear magnetoelectric coefficient of h-LuFeO3 (αzz<6ps/m) is estimated by magnetoelectric force microscopy measurements. [ABSTRACT FROM AUTHOR]