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A series of Pd1−xFex alloy epitaxial films (x = 0, 0.038, 0.062, and 0.080), a material promising for superconducting spintronics, was prepared and studied with ultrafast optical and magneto-optical laser spectroscopy in a wide temperature range of 4–300 K. It was found that the transition to the ferromagnetic state causes a qualitative change of both the reflectivity and the magneto-optical Kerr effect transients. A nanoscale magnetic inhomogeneity of the ferromagnet/paramagnet type inherent in the palladium-rich Pd1−xFex alloys reveals itself through the occurrence of a relatively slow, 10–25 ps, photoinduced demagnetization component following a subpicosecond one; the former vanishes at low temperatures only in the x = 0.080 sample. We argue that the 10 ps timescale demagnetization originates most probably from the diffusive transport of d electrons under the condition of nanoscale magnetic inhomogeneities. The low-temperature fraction of the residual paramagnetic phase can be deduced from the magnitude of the slow reflectivity relaxation component. It is estimated as ≈30% for x = 0.038 and ≈15% for x = 0.062 films. The minimal iron content ensuring the magnetic homogeneity of the ferromagnetic state in the Pd1−xFex alloy at low temperatures is about 7–8 atom %.

Thin epitaxial films of metals on insulating substrates are essential for many applications, as conducting layers, in magnetic devices or as templates for further growth. In this work, we report on the growth of epitaxial Ru films on single-crystalline Al 2 O 3 (0001) substrates by magnetron sputtering and their subsequent systematic characterization using Rutherford backscattering spectrometry of He ions both in random and in channeling conditions. We include results of a Ru(0001) single crystal for comparison. Analysis of channeling shows that films thicker than 35 nm grow with (0001) orientation, a well-defined epitaxial relation with the substrate and a high degree of crystal quality, comparable to the Ru(0001) single crystal. Thinner films of down to 7 nm in thickness, for which relaxation of epitaxial strain is not complete, produce a similar degree of dechanneling. The surface of the films can be prepared in a clean and ordered state in order to allow further epitaxial growth on top. [Display omitted] • Epitaxial Ru films up to 100 nm were grown by magnetron sputtering on Al 2 O 3 (0001) • RBS/Channeling shows well defined epitaxial relation of films with substrate • Minimum yields and dechanneling show crystalline quality similar to Ru(0001) • Surface of films is well ordered as determined by LEED • Further epitaxial growth of nanostructures on top of Ru/Al 2 O 3 (0001) is possible. [ABSTRACT FROM AUTHOR]

A series of Pd 1- x Fe x alloy epitaxial films ( x = 0, 0.038, 0.062, and 0.080), a material promising for superconducting spintronics, was prepared and studied with ultrafast optical and magneto-optical laser spectroscopy in a wide temperature range of 4-300 K. It was found that the transition to the ferromagnetic state causes a qualitative change of both the reflectivity and the magneto-optical Kerr effect transients. A nanoscale magnetic inhomogeneity of the ferromagnet/paramagnet type inherent in the palladium-rich Pd 1- x Fe x alloys reveals itself through the occurrence of a relatively slow, 10-25 ps, photoinduced demagnetization component following a subpicosecond one; the former vanishes at low temperatures only in the x = 0.080 sample. We argue that the 10 ps timescale demagnetization originates most probably from the diffusive transport of d electrons under the condition of nanoscale magnetic inhomogeneities. The low-temperature fraction of the residual paramagnetic phase can be deduced from the magnitude of the slow reflectivity relaxation component. It is estimated as ≈30% for x = 0.038 and ≈15% for x = 0.062 films. The minimal iron content ensuring the magnetic homogeneity of the ferromagnetic state in the Pd 1- x Fe x alloy at low temperatures is about 7-8 atom %., (Copyright © 2022, Petrov et al.)

Abstract: We have observed an exchange bias effect on field cooling of epitaxial magnetite, Fe3O4, films on MgO (100) substrates. We attribute this effect to the presence of antiphase boundaries (APBs). Magnitude of the exchange bias field (He) strongly depends on the thermo-magnetic history of the sample. The strength of the He was found to increase with an increase in film thickness and is attributed to the strain driven redistribution of atoms in the vicinity of APBs leading to enhanced antiferromagnetic exchange interactions. [Copyright &y& Elsevier]

The CoSi2, NiSi2, NaSi2 and BaSi2 thin epitaxial films have been obtained by molecular beam epitaxy and ion implantation. The growth mechanisms as well as the composition, electron and crystalline structure of these films were studied and determinate. It was shown that NiSi2, CoSi2, BaSi2 and NaSi2 epitaxial films crystallise as cubic lattice, and the bond between atoms of metal and Si has ionic-covalent nature. It was determined that the metal silicide films are heterostructure relatively Si and their width band gap make up 0.5–0.7 eV. [Copyright &y& Elsevier]

Resent results concerning epitaxial Fe3O4(001) films grown by reactive deposition on MgO(001) substrates as well as obtained by oxidation of epitaxial Fe(001) films are reviewed. Conversion electron Mo¨ssbauer spectroscopy (CEMS) performed in and ex situ was used to check the stoichiometry and electronic properties with monolayer resolution. Size effects were reflected in reduction of the Verwey temperature for the film thickness less than 50 nm. With further decrease in thickness, the films showed strong deviation from the bulk properties due to formation of a magnesium rich phase near the MgO/Fe3O4 interface. Surface oxidation to γ-Fe2O3, which can be reversed by annealing, was found using CEMS. The atomic scale surface characterization was accomplished for the first time in situ by the scanning tunneling microscopy, which revealed details of the surface reconstruction and termination. [Copyright &y& Elsevier]