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We have investigated the effects of low-energy ion beam irradiations using argon clusters on the chemical and electronic properties of LaAlO3/SrTiO3 (LAO/STO) heterointerfaces by combining x-ray photoelectron spectroscopy (XPS) and electrical transport measurements. Due to its unique features, we demonstrate that a short-time cluster ion irradiation of the LAO surface induces significant modifications in the chemical properties of the buried STO substrate with (1) a lowering of Ti atoms oxidation states (from Ti4+ to Ti3+ and Ti2+) correlated to the formation of oxygen vacancies at the LAO surface and (2) the creation of new surface states for Sr atoms. Contrary to what is generally observed by using higher energy ion beam techniques, this leads to an increase of the electrical conductivity at the LAO/STO interface. Our XPS data clearly reveal the existence of dynamical processes on the titanium and strontium atoms, which compete with the effect of the cluster ion beam irradiation. These relaxation effects are in part attributed to the diffusion of the ion-induced oxygen vacancies in the entire heterostructure since an increase of the interfacial metallicity is also evidenced far from the irradiated area. This paper highlights the possibility of tuning the electrical properties of LAO/STO interfaces by surface engineering, confirming experimentally the intimate connection between LAO chemistry and electronic properties of LAO/STO interfaces.

We report experiments on the static magnetic properties of ${\text{YFeO}}_{3}$ under magnetic fields up to 28 T. We studied an untwined single crystal, a sintered powder and a film of ${\text{YFeO}}_{3}$ epitaxially grown by pulsed laser deposition. We proved the relevance of a little used technique, the torque magnetometry, for investigating films having Dzyaloshinsky-Moriya interaction under very high fields. A dedicated framework for analyzing the torque signal in this particular case is also given. We proposed an original model proposed to explain the irreversibility based on the comparison of the morphologies of an experimental study made on purpose. One of the consequences of the particular morphology of films is that the net magnetic moment of the film can be permanently set perpendicular to the substrate plane, giving rise to an effective perpendicular magnetic anisotropy with a coercive field as high as 3 T at room temperature.