Low-impurity ferromagnetism remains a challenging problem without a unified theoretical description. We systematically investigate Pd1-xMex alloys (Me = Mn, Fe, Co, Ni) using first-principles DFT across impurity concentrations from 1 to 100 at.%. Our refined methodology accurately predicts magnetic and electronic properties, tracing the transition from isolated magnetic impurities to bulk ferromagnetism. We identify critical concentrations where spontaneous magnetization appears and observe a sharp onset of magnetic ordering at dilute limits. For Mn-and Ni-doped systems, the critical concentration is found near 3 at.%, corresponding to ferrimagnetic ordering in both cases. In contrast, Fe-and Co-doped alloys exhibit no distinct critical threshold within the studied range, suggesting that the onset occurs below 1 at.%. Pd-Fe displays ferrimagnetic behavior, while Pd-Co is in ferromagnetic state. Overall, the maximal magnetic moments per impurity are similar for all series, lying within 13-15 mu B. Moreover, electronic structure analysis, including atomic, spin-, and orbital-resolved density of states, clarifies the formation and spatial evolution of magnetic clusters. This work provides new theoretical insights into the microscopic mechanisms underlying low-impurity ferromagnetism in Pd-based alloys.

The nature of low-impurity ferromagnetism remains a challenging problem in the solid-state community because of the strong dependence of magnetic properties on composition, concentration, and structural geometry of diluted alloys. To shed light on this complexity, we conducted a comprehensive density functional theory investigation of magnetocrystalline anisotropy in Fe, Co, Pd_0.97Co_0.03 systems across bulk, monolayer, and thin-film geometries. By employing advanced noncollinear spin–orbit coupling calculations, we accurately evaluated the magnetocrystalline anisotropy energies, complemented by detailed atomic-, spin-, and orbital-resolved density of states analyses. Our findings reveal that Fe and Co exhibit contrasting easy-axis orientations that strongly depend on the system geometry. Remarkably, even a low Co doping level of 3 at.

In this paper, results of experimental studies and modeling of standing spin-wave spectra and their temperature evolution in graded Pd-Fe alloy thin magnetic films are presented. Studied sample series include 200-nm thick epitaxial Pd1-xFex films on MgO (001): two with the linear (0.02. .. 0.10 and 0.12... 0.18 x-ranges), one with the sine and one with the cosine (both with 0.02... 0.10 x-range) iron distribution profiles. Versatile spin-wave excitation patterns were obtained, and their pronounced evolution with temperature was observed. Importantly, temperature affects spectra not only in a trivial way via the temperature dependence of magnetization and related quantities, but also through modification of magnetic phase structure of a film due to the Curie temperature crossing by its fraction(s). Continuous at low temperatures magnetization profile becomes discontinuous or significantly altered at elevated ones. Standing spin-wave resonance spectra were modeled using a semiclassical Landau-Lifshitz approach. Based on the modeling, temperature dependences of the spin-wave stiffness D and magnitudes of the interface alpha inter and surface alpha surf pinning constants were obtained. It is shown that, besides a compositional grading of magnetic thin films, the temperature variation is a powerful tool for modifying the magnetization profile and thus, for a flexile tuning of spin-wave spectra.

A comparative study of the magnetic properties of a palladium–cobalt alloy with an impurity content of up to 10 at

In this work, we have studied the microstructure and unusual ferromagnetic behavior in epitaxial tin dioxide (SnO2) films implanted with 40 keV Co+ ions to a high fluence of 1.0 × 1017 ions/cm2 at room or elevated substrate temperatures. The aim was to comprehensively understand the interplay between cobalt implant distribution, crystal defects (such as oxygen vacancies), and magnetic properties of Co-implanted SnO2 films, which have potential applications in spintronics. We have utilized scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), differential thermomagnetic analysis (DTMA), and ferromagnetic resonance (FMR) to investigate Co-implanted epitaxial SnO2 films. The comprehensive experimental investigation shows that the Co ion implantation with high cobalt concentration induces significant changes in the microstructure of SnO2 films, leading to the appearance of ferromagnetism with the Curie temperature significantly above the room temperature. We also established a strong influence of implantation temperature and subsequent high-temperature annealing in air or under vacuum on the magnetic properties of Co-implanted SnO2 films. In addition, we report a strong chemical effect of ethanol on the FMR spectra. The obtained results are discussed within the model of two magnetic layers, with different concentrations and valence states of the implanted cobalt, and with a high content of oxygen vacancies.

In this work, we have studied microstructure and unusual ferromagnetic behavior in cobalt (Co)-implanted epitaxial tin dioxide (SnO2) films. The study was aimed to provide a comprehensive understanding of the interplay between cobalt implant distribution, crystal defects, such as oxygen vacancies, and magnetic properties in Co-implanted SnO2 films, which has potential applications in spintronics and memristor devices. The scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM), differential thermo-magnetic analysis (DTMA), and ferromagnetic resonance (FMR) were employed for investigations of SnO2 films implanted with 40 keV Co+ ions at room or the elevated temperatures of substrate. The experimental data showed that the Co ion implantation with high fluence of 1.0 1017 ions/cm2 induces significant changes in the microstructure of SnO2 films, leading to the appearance of ferromagnetism with the Curie temperature significantly above room temperature. Strong influence of implantation temperature and subsequent high-temperature annealing in air or in vacuum on magnetic properties of Co-implanted SnO2 films were established. Moreover, the chemical effect of ethanol on FMR spectra were observed. The obtained results are discussed within the model of two magnetic layers with different concentration and valence states of the implanted cobalt and with high content of oxygen vacancies.

This study presents the initial results of developing a technology for synthesizing a flexible superconducting magnesium diboride composite on a Hastelloy®-C276TM substrate coated with Al2O3/Y2O3/MgO/LaMnO3 buffer layers. The superconducting composite was deposited by magnetron sputtering from two Mg and B targets, followed by vacuum annealing at various substrate temperatures ranging from 400 °C to 700 °C. The superconducting transition temperature T c ≈ 22 K, with a transition width ΔT ≈ 1 K, and critical current J c ≈ 500 kA cm−2 (T= 5 K, H = 2 T) and J c ≈ 11 kA cm−2 (T = 15 K, H = 2 T) at the optimal annealing temperature of 400 °C.

The static magnetic properties were experimentally studied and magnetization reversal was modeled in an epitaxial thin film of the L10 phase of the PdFe compound and the PdFe/W/PdFe heterostructure on MgO (001) substrates. It was shown that the PdFe/W/PdFe heteroepitaxial structure at an α-W layer thickness of ∼0.7 nm is an artificial antiferromagnet with perpendicular magnetic anisotropy and an exchange integral of J ≃ 1.7 ×10^ - 3 J/m^2 . Micromagnetic modeling of the equilibrium domain structure and its evolution in an external magnetic field made it possible to satisfactorily describe the magnetization reversal curve of the studied thin-film heterostructure.

An epitaxial film of a Pd–Fe alloy with a thickness of 202 nm was synthesized with an iron concentration varying in depth from 2 to 10 at

This study demonstrates capabilities of a molecular beam epitaxy method for the deposition of ferromagnetic Pd–Fe alloy thin films with variable compositions across film thickness. It is proposed as a technological route to synthesize graded magnetic materials possessing unusual physical properties. A particular approach to realize a concentration profile through temperature control of an effusion cell during deposition is described in detail. Using this technique, graded ferromagnetic films were synthesized and characterized to reveal the possibility of controlling the spectrum of standing spin waves in them. Limitations of creating Pd–Fe films magnetically profiled across the thickness are discussed, associated with the thermal inertia of effusion cells and possible phase separation.

Results are presented from studying the magnetostatic and magnetoresonant properties of a thin-film bilayer Fe3Al/Pt structure synthesized via molecular beam epitaxy. Magnetometry and ferromagnetic resonance data indicate the four-fold in-plane magnetocrystalline anisotropy of the Fe3Al layer. The magnetic field dependence of the voltage induced by the inverse spin Hall effect is measured under conditions of spin pumping, and the quantitative characteristic of the spin-charge transformation in platinum (the spin Hall angle) is estimated as θSH = 0.030 ± 0.005.

In the article, a hydrogen exchange between the Zr-1%Nb alloy (E110) and the gas ambient was experimentally studied when the samples were irradiated with deuterium and argon plasma ions. It has been established that, upon irradiation with deuterium plasma ions with an energy of E = 650 eV/at, the enhanced absorption of deuterium exceeds the release of hydrogen initially contained in the samples, which leads to their loading with hydrogen isotopes. Adding 30 at.% oxygen to the plasma-forming gas or raising the sample temperature from T = 450 K to T = 600 K, significantly reduces the content of hydrogen isotopes in the sample. Based on the aggregate data obtained by atomic and ion irradiation, a mechanism of hydrogen exchange between zirconium alloy and gas ambient is proposed. The process includes three stages: reactions on the oxidized surface of the zirconium alloy (surface hydroxylation and formation of water molecules); reactions at the metal-oxide interface; transfer of hydrogen isotopes through the surface oxide layer in both directions due to hopping between neighboring oxygen ions. Surface reactions caused by irradiation of atoms and ions trigger the hydrogen exchange. The proposed model agrees with the experimental data on the irradiation of the E110 alloy with atoms and ions of hydrogen isotopes.

An epitaxial film of the Pd-Fe alloy 116 nm thick with an iron concentration varying in depth from 2 at.% to 50 at.% has been synthesized. An experimental depth distribution profile of iron was obtained as a result of stepwise etching of the film surface with Ar+ ions. Profiling showed that, as a result of annealing, the impurity was redistributed in the film, and a layer of the L10-phase with a constant concentration was formed near the film surface. After removal of the L10-phase, the film exhibits easy-plane anisotropy. The study of spin-wave resonance spectra showed the presence of several modes of standing spin waves, the number of which depends on the residual film thickness.

An epitaxial film of the Pd-Fe alloy 116 nm thick with an iron concentration varying in depth from 2 at.% to 50 at.% has been synthesized. An experimental depth distribution profile of iron was obtained as a result of stepwise etching of the film surface with Ar + ions. Profiling has shown that, as a result of annealing, the impurity was redistributed in the film, and a layer of the L1 0 -phase with a constant concentration was formed near the film surface. After removal of the L1 0 -phase, the film exhibits "easy-plane" anisotropy. The study of spin-wave resonance spectra showed the presence of several modes of standing spin waves, the number of which depends on the residual film thickness. Keywords: graded magnetic materials, molecular beam epitaxy, palladium-iron alloys, X-ray diffraction, spin-wave resonance.

We have investigated the low-temperature magnetoresistive properties of a thin epitaxial Pd0.92Fe0.08 film at different directions of the current and the applied magnetic field. The obtained experimental results are well described within an assumption of a single-domain magnetic state of the film. In a wide range of the appled field directions, the magnetization reversal proceeds in two steps via the intermediate easy axis. An epitaxial heterostructure of two magnetically separated ferromagnetic layers, Pd0.92Fe0.08/Ag/Pd0.96Fe0.04, was synthesized and studied with dc magnetometry. Its magnetic configuration diagram has been constructed and the conditions have been determined for a controllable switching between stable parallel, orthogonal, and antiparallel arrangements of magnetic moments of the layers.

Palladium-iron alloys produced by high-dose implantation of iron ions into epitaxial palladium films were investigated with the ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM) techniques. The samples reveal distinct multiple FMR responses depending on the dose of iron ion implantation. The post-implantation annealing at 770 K does not bring the implanted films to a homogeneous solid solution state, as might be expected from the Pd-Fe phase diagram. On the contrary, the system approaches a stable state composed of several magnetic phases. FMR spectra exhibit an angular behavior specific for a stack of interacting magnetic layers. This observation, correlated with the magnetometry data, indicates that the palladium-iron binary alloy has a previously unknown tendency towards spinodal decomposition into isostructural phases with well-defined iron concentrations and, accordingly, with different temperatures of ferromagnetic ordering and saturation magnetizations.

Ultrafast dynamics of the reflection coefficient of a thin epitaxial silver film on- and off- plasmon resonance has been studied using pump-probe technique. We demonstrate that modification of surface plasmon excitation conditions originates from a change in both real and imaginary components of the dielectric constant. The map of the reflection coefficient of the film versus wavelength and angle of incidence of light was measured.

We have performed full-stack research of Pd1−xFex and Pd1-xCox (x = 0.01–0.1) alloys. At the first stage, the occurrence of impurity ferromagnetism in the considered alloys was studied employing the density functional theory (DFT). At the second stage, magnetic impurities of Fe and Co atoms were implanted into epitaxial Pd thin films to verify the DFT results. The magnetic properties of implanted Pd films were investigated by a Vibrating Sample Magnetometer (VSM) in the temperature range from 5 to 300 K. It has been established that VSM results are in good agreement with ab initio calculations. In particular, 4 and 5 µB for Co found from VSM for x = 0.025 and x = 0.035 agree well with DFT value of 5.5 µB for x = 0.025.

We report investigation of ferromagnetic resonance phenomenon in ferromagnetic thin films with essentially non-uniform composition. Epitaxial Pd-Fe thin film with linear distribution of Fe content across the thickness is used as the model material. Anomalous perpendicular standing spin waves are observed and quantified using the collective dynamic equation. Numerical analysis yields the exchange stiffness constant for diluted Pd-Fe alloy $D=2A/\mu_0M_s=15$~T$\cdot$nm$^2$ and the ratio of the effective magnetization to the saturation magnetization $M_{eff}/M_s=1.16$. It is demonstrated that, overall, engineering of thin films with non-uniform composition across the thickness can be used for high-frequency or low-field magnonic operations using exchange spin waves.