The article presents the results of magnetocrystalline anisotropy (MCA) investigation of Y2(FexCo1-x)17 (x = 0.03-0.50) rare-earth quasi-binary bulk crystal samples and their hydrides. The specific magnetization curves m (H) were measured in the wide temperature range for the original Y2(FexCo1-x)17 samples and for the corresponding hydrides. Magnetocrystalline anisotropy constants K1, K2 were calculated, temperature and compositional dependence curves were plotted based on m ( H ) data. The temperature dependences of specific saturation magnetization m s ( T ) and first anisotropy constant K 1 ( T ) were analyzed to determine temperature behavior patterns, estimate the Curie temperature Tc and predict the spin-reorientation transitions. The first anisotropy constant, saturation magnetization and Curie temperature compositional dependences of original Y2(FexCo1-x)17 and hydrogenated Y2(FexCo1-x)17Hy samples were compared to identify the hydrogenation effect on the magnetic properties of investigated compounds. The revealed patterns were explained in terms of the crystal structure of the compounds.

The results of an experimental study of the magnetic domain structure on the basal plane of RFe11Ti single crystals (R=Y, Gd, Ho, Er) by magnetic force microscopy are presented. At room temperature, the compounds are characterized by magnetocrystalline anisotropy of the "easy axis" type. Based on the magnetic force microscopy data, the sizes of domains on the basal plane of the samples were determined. Using the Bodenberger-Hubert method, the surface energy density of domain walls gamma was determined for all compounds based on the magnetic force microscopy data: YFe11Ti - 4,05 mJ/m(2), GdFe11Ti - 5,93 mJ/m(2), HoFe11Ti - 4,97 mJ/m(2), ErFe11Ti - 2,98 mJ/m(2). The cube counting method was used to calculate the fractal dimension D-L of the stray fields of the domain structure at different heights from the surface (0,1 - 9 mu m). D-L on the surface of the z(0) sections has values of 2,62 for compounds with R = Y, Gd, Ho and 2,72 for R=Er. For all samples, D-L has a maximum near the surface.

The main aim of the present work is to analyze the magnetocrystalline anisotropy (MCA) energy function of uniaxial crystals and to derive analytical expressions for the domain wall (DW) energy taking into account two MCA constants. Thus, the article presents a detailed analysis of the magnetocrystalline anisotropy energy function of uniaxial crystals taking into account two MCA constants (K-1, K-2). The values of the MCA energy extremes and the position of the easy magnetization directions (EMD) and hard magnetization directions (HMD) were determined. The MCA diagram was plotted in "K-1"-"K-2" coordinates. Six types of MCA have been found for uniaxial crystals. Two of them are simple with one maximum and one minimum of the E-A(theta) function, and four are complex with two absolute and one local extreme for each. It is shown that E-A(K-1, K-2) function has the smallest difference between the maximum and minimum values equal to |K-1|/4 and the smallest angle between EMD and HMD equal to pi/4 when the K-1 + K-2 = 0 condition is met. Analytical expressions for the 180 degrees Bloch domain wall energy surface density (gamma) were derived for uniaxial crystals with each MCA type. It is found that the gamma(K-1, K-2) function has a minimum, equal to gamma=2 root A|K-1| when the relation K-1 + K-2 = 0 between MCA constants is satisfied. The derived analytical expressions are useful for a detailed spin-reorientation transition analysis. To illustrate this, examples of the application of the obtained results to MCA analyses of real crystals and DW energy calculations are given.

The magnetization curves of the Y2(FexCo1 – x)17 compounds were measured in the temperature range of 300–923 K along easy and hard magnetization directions. The magnetization curves were analyzed, and the magnetocrystalline anisotropy constants K1, 2 of the samples were calculated. The temperature and composition dependences of the anisotropy constants K1, 2 and the saturation magnetization Ms were discussed. It was shown that, with increasing relative iron concentration in the samples, the first anisotropy constant K1 increases and reaches a maximum value of 5.1 × 105 J m–3 at x = 0.29.

The results of an experimental study of magnetization reversal processes of (R,Zr)(Co,Cu,Fe)(Z) (R = Sm, Gd) alloys taking into account micro- and nanostructure are presented. To create a highly coercive state in the samples, they were isothermally annealed at 800 degrees C for 8-24 hours. The duration of annealing affects the formation of the nanostructure of alloys of this type. Based on magnetic measurements performed using a vibration magnetometer, magnetic hysteresis loops and graphs of the dependence of the coercive force on the chemical composition and duration of heat treatments were obtained, and the range of changes in the temperature coefficient of magnetic induction was determined depending on the relative content of Sm and Gd in the samples. Data on micro- and nanostructure were obtained using optical and scanning probe microscopy. The correlation relationships between the micro- and nanostructure parameters and the magnetic properties of the studied alloys are described. It was found that the highest values of the coercive force are achieved in an alloy in which the value is x = 0,5.

Методом атомно-силовой микроскопии получены изображения наноструктры составляющих гетерогенного интерметаллида SmCoCuFeZr в высококоэрцитивном состоянии. На микроуровне в сплавах выделили два типа областей (фазовых составляющих) отличающихся по интегральному элементному составу и интервалам коэрцитивности. На основе данных атомно-силового микроскопа проводится анализ фрактальных характеристик поверхности этих областей. Показано, что фрактальная размерность наноструктуры коррелирует с локальной коэрцитивностью фазовых составляющих. Фазовая составляющая с относительно низкой коэрцитивностью демонстрирует возможность существования структур с фрактальной размерностью в диапазоне 2,396 - 2,475, что соответствует умеренно развитому фрактальному рельефу. При этом высококоэрцитивная составляющая с регулярной наноструктурой характеризуется более высокой фрактальной размерностью 2,452 - 2,508, а на отдельных участках образца встречались области с фрактальной размерностью до 2,577 . The atomic force microscopy was used to obtain images of the nanostructure of components of a heterogeneous intermetallic SmCoCuFeZr compound in a highly coercive state. At the microlevel, two types of regions were distinguished in the alloys, differing in integral elemental composition and coercivity intervals. Based on the atomic force microscopy data, an analysis of the fractal characteristics of the surface is carried out on both of the above types of areas. It is shown that the fractal dimension of the nanostructure correlates with the local coercivity of the phase components. The phase component with a relatively low coercivity demonstrates the possibility of the existence of structures with fractal dimensions in the 2,396 - 2,475 range corresponding to a moderately developed fractal relief. In this case, the high-coercive component with a regular nanostructure is characterized by a higher fractal dimension of 2,452 - 2,508, and in some areas of the sample there were regions with a fractal dimension up to the value of 2,577.

The obtaining of track membranes is one of the applications of radiation technologies. Porous structure of such membranes could be changed by will and could be used for matrix synthesis. Matrix synthesis based on specially prepared porous matrixes was used in this work for obtaining of nanowires of Iron and Nickel. Magnetic –force microscopy was applied for fro visualization of these nanowires embedded in host matrix. The dependence of magnetic-force images of nanowires position inside matrix and on orientation of external magnetic field was investigated.