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We studied the effect of Mn on the structure and properties of Cd3−xMnxAs2 crystals with x = 0–0.24, synthesized by direct fusion of high-purity elements. Obtained X-ray diffraction patters suggest that the incorporation of Mn promotes a structural phase transition from primary α-Cd3As2 (x = 0) phase to the α''– Cd3As2 (x = 0.24) phase, while at intermediate compositions both phases can coexist. In addition, the increase of Mn content results in the decrease of lattice cell parameters, which effectively saturates for x > 0.13. Microstructural, calorimetric and magnetometry studies suggest that at high Mn content (x = 0.24) secondary MnAs phase appears. Using obtained results, we estimated the solubility limit of Mn in Cd3As2 as x~0.13, which corresponds to the formation of ternary Cd3−xMnxAs2 compound where Cd atoms are partially substituted by Mn. Formation of ternary compound was also suggested by the results for Cd3As2 + MnAs composite systems, where we also observed the presence of CdAs2 phase, which is a byproduct of corresponding reaction. Additional studies suggested that the CdAs2 phase formation in composite system can be prevented if one uses the Cd3−xMnxAs2 compound instead of pure Cd3As2 as a matrix material.

BaFe12O19 films on Al2O3 (001) substrates were synthesized by ion beam deposition with post-annealing. Three deposition regimes were applied, resulting in unique surface morphology and X-ray diffraction patterns of obtained samples. In the first case, the deposition process was interrupted several times and the sample was subjected to ex situ annealing at 900 °C after each interruption. As a result, a film with high texture degree (about 97 %) was obtained. In the second case, the deposition process was interrupted the same number of times, but during each pause the film remained in the vacuum chamber for 10 min at 300 °C. This approach resulted in a medium texture degree of the sample (about 72 %). In the third case, there were no breaks in the deposition process and the texture of the resulting film was extremely poor. An explanation for the observed differences is proposed. To improve the texture of the films, a second annealing at 1280 °C for 10 h was applied, but as a result strong interdiffusion and misorientation of the grains occurred.

Doping by Mn breaks the time-reversal and crystal symmetry of Cd 3 As 2 , splits Dirac cones and changes band structure. We study these changes using both DFT calculations and magnetotransport measurements. Our band structure of Cd 3 As 2 is confirmed by calculations of dielectric tensor and reflectivity consistent with an experiment. Calculations take into account the n -carrier density of Cd 3 As 2 samples ∼ 1 · 10 18 cm − 3 which shifts the Fermi level by e F ∼ 50 meV. The Mn-doping of Cd 3 As 2 is simulated with the Cd 46 Mn 2 As 32 cell for 9 configurations of Mn atoms. Our simulation shows the preference for antiferromagnetic spin order and tendency towards Mn clustering. Doping by Mn causes transition of Cd 3 As 2 into a trivial topological state with a gap of E g ≈ 40 meV. Our experimental studies of (Cd 1 − x Mn x ) 3 As 2 show that a negative sign of magneto-conductivity is observed at x = 0 and 0.017, but changes to a positive one at x = 0.033 . We argue, this sign change is closely connected with the gap opening and is basically controlled by the ratio E g / e F .

Phase diagram in the ZnSiAs 2 –MnAs nanocomposite system was studied by Х-ray, DTA and SEM. The system has an eutectic character. The coordinates of eutectic are 87±1 mol% MnAs and 847±10 °C. The eutectic consists of the manganese arsenide lattice with ZnSiAs 2 inclusions.

The ZnAs2–MnAs system, characterized by X-ray powder diffraction, differential thermal and microstructure studies, is of the eutectic type, with the coordinates of eutectic 73 mol% ZnAs2 and 27 mol% MnAs and Tm = 716 °C. The solubility of MnAs in ZnAs2 is lower 1 mol%. Alloys of ZnAs2 with MnAs are ferromagnetic with Tc ≈ 318 K, their magnetization being increased with raising the MnAs content.

Barium hexaferrite thin films were prepared by ion beam deposition on sapphire (1 0 2) single crystal substrates. The structural properties of the films were analyzed by means of X-ray diffraction, atomic force microscopy, magnetic force microscopy and scanning electron microscopy. The obtained results were interpreted as a presence of layered structure with different types of texture and its formation mechanism is proposed. The significant influence of BaFe12O19 thickness on its microstructure was observed. Films obtained under certain conditions are potentially fit for further growing of oriented hexaferrite with out-of-plane orientation of c-axis.