This work focuses on the generation of ferromagnetism at the surface of anatase TiO 2 films by low-energy ion irradiation. Controlled Ar +-ion irradiation resulted in a thin (∼10) nm ferromagnetic surface layer. The intrinsic origin and robustness of the magnetic order has been characterized by x-ray magnetic circular dichroism at room temperature revealing that a Ti band is spin-polarized. These results, together with density functional theory calculations, indicate that Ti vacancy-interstitial pairs are responsible for the magnetic order. Superconducting quantum interference device measurements show the existence of a perpendicular magnetic anisotropy and a low remanent magnetization. Magnetic force microscopy reveals that this low remanence is due to oppositely aligned magnetic domains with magnetization vectors normal to the main surface. The weak domain-wall pinning, the magnetic anisotropy, together with the simplicity of the preparation method, open up interesting possibilities for future applications. As an example, single domain patterns of ∼1 μm width and several μm length can be easily prepared.

Nucleation and early growth of Li metal is critical to the performance of anode-free solid-state batteries. We report the use of amorphous carbon deposited by direct current magnetron sputtering as...

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The ion beam sputtering of a metallic Ti and a ceramic TiO 2 target by bombardment with oxygen ions was investigated systematically. Emphasis was put on the properties of the secondary particles emitted from the target, namely, the angular distribution of the sputtered Ti and the energy distribution of the secondary ions. Ion energies of 0.5, 1.0, and 1.5 keV and incidence angles of 0°, 30°, and 60°were used. The angular distribution of the flux of sputtered Ti particles was determined by measuring the thickness of TiO 2 films that were deposited under emission angles in the range between −40°and +80°. An empirical formula was used to describe the angular distribution as a superposition of an isotropic and an anisotropic cosinelike function. Increasing the ion energy or decreasing the ion incidence angle leads to a more isotropic emission of the sputtered Ti particles. The mass and energy distribution of the secondary ions were measured using an energy-selective mass spectrometer. The most prevalent ion species are O + , O 2 + , Ti + , and TiO +. Ion energy and sputtering geometry, i.e., the combination of an ion incidence angle and an emission angle, were found to have a strong influence on the energy distribution of the secondary ions.