Recently, perpendicular magnetic anisotropy (PMA) and its voltage control (VC) was demonstrated for Cr/Fe/MgO. In this study, we shed light on the origin of large voltage-induced anisotropy change in Cr/Fe/MgO. Analysis of the chemical structure of Cr/Fe/MgO revealed the existence of Cr atoms in the proximity of the Fe/MgO interface, which can affect both magnetic anisotropy (MA) and its VC. We showed that PMA and its VC can be enhanced by controlled Cr doping at the Fe/MgO interface. For Cr/Fe (5.9 Å)/Cr (0.7 Å)/MgO with an effective PMA of 0.8 MJ/m³, a maximum value of the voltage-controlled magnetic anisotropy (VCMA) effect of 370 fJ/Vm was demonstrated due to Cr insertion.

An in-plane spin-reorientation transition occurring during the growth of epitaxial Fe films on W(110) was studied in~situ by using the nuclear resonant scattering of synchrotron radiation. The spin-reorientation transition originates at the Fe/W(110) interface and proceeds via a noncollinear spin structure resembling a planar domain wall that propagates towards the surface with increasing film thickness.

Ultrathin (111)-oriented polar iron oxide films were grown on a Pt(111) single crystal either by the reactive deposition of iron or oxidation of metallic iron monolayers. These films were characterized using low-energy electron diffraction, scanning tunneling microscopy, and conversion electron M\"ossbauer spectroscopy. The reactive deposition of Fe led to the island growth of Fe3O4, in which the electronic and magnetic properties of the bulk material were modulated by superparamagnetic size effects for thicknesses below 2 nm, revealing specific surface and interface features. In contrast, the oxide films with FeO stoichiometry, which could be stabilized as thick as 4 nm under special preparation conditions, had electronic and magnetic properties that were very different from their bulk counterpart w\"ustite. Unusual long-range magnetic order appeared at room temperature for thicknesses between 3 and 10 monolayers, the appearance of which requires severe structural modification from the rock-salt structure.

The chemical, electronic and magnetic structures of the interfaces between Fe(001) and MgO(001) thin films were studied using conversion electron Mössbauer spectroscopy (CEMS). A 1 ML thick ⁵⁷Fe probe located at either of the interfaces in the MgO/⁵⁶Fe/MgO epitaxial structure enabled precise measurements of the interfacial hyperfine interactions. Analysis of the CEMS spectra showed that both the “MgO/Fe” and “Fe/MgO” interfaces are partially oxidized (63% and 86%, respectively), although, despite good crystallinity, no well-defined iron oxide phases were detected. At the “MgO/Fe” interface, 14% of the oxidized Fe sites were found to be defective (located at steps, corners or kinks). The “Fe/MgO” interface, from which the formation of ⁵⁷Fe islands of at least 3 ML in height was inferred, was found to be almost defect-free. No modification of the hyperfine parameters of Fe atoms located away from the interface was detected for “Fe/MgO,” in contrast with the “MgO/Fe” interface. Approximately 6% of the probe layer diffused into the MgO films at both interfaces.

Fe³⁺/TiO₂/zeolite Y photocatalyst synthesized by using sonophotodeposition method was compared with photocatalysts prepared by simple photodeposition and sonodeposition methods in order to clarify the role of light irradiation and ultrasounds while they are used simultaneously. To gain an insight into the mechanism of this method a detailed characterization of the photocatalysts was carried out by means of the following techniques: UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, Mössbauer measurements and photocatalytic test reaction. Basing on the results from these techniques the chemical role of light and mainly mechanical role of ultrasound were observed. The selective photocatalytic oxidation of benzyl alcohol into benzaldehyde in liquid phase was a test reaction verifying the utility of the prepared materials. The best photocatalytic efficiency in this reaction was performed by photocatalyst synthesized using compilation of ultrasound energy with photoexcitation.