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1.
The results of experimental and theoretical studies of the low-temperature properties of FeSi crystals are presented. The specific features of the magnetic susceptibility are shown to be related to the superparamagnetic behavior of impurity clusters. The thermomagnetic hysteresis phenomena observed are explained using the model of exchange-coupled clusters.  相似文献   
2.
The electrical and magnetic properties of the nanodiamond composites comprising nanodiamond, pyrolytic carbon, and nanosized pores were studied. The composites are p-type semiconductors and their resistance decreases by 12 orders of magnitude as the pyrocarbon-to-diamond ratio γ increases from 0 to 80 wt %. Evidence for paramagnetic properties of the nanodiamond composites was obtained. The observed properties are explained by increased concentration of surface Tamm states. The paramagnetic properties are explained in terms of the electron spins localized on the nanodiamond surface in the composite.  相似文献   
3.
Results of studying the specific features of formation of the crystal structure and distribution of iron cations over the sites in the DyFeTi2O7 compound have been presented and the comparison with the GdGaTi2O7 isostructural compound has been performed. The atomic disorder in the distribution of the Fe3+ ions over structural sites in the DyFeTi2O7 compound is confirmed by the Mössbauer spectroscopy and X-ray diffractometry. The results of magnetic measurements in the low-temperature region have revealed an inflection point in the temperature dependence of the magnetic moment and its dependence on the magnetic prehistory of the sample. The obtained experimental data suggest that there is a spin glass state with freezing point T f = 6 K in the DyFeTi2O7 compound.  相似文献   
4.
Compounds in the CrS-FeS system over a wide range of compositions are investigated by Mössbauer spectroscopy. The analysis of the Mössbauer spectra demonstrates that the materials under investigation are substitutional solid solutions with a random distribution of chromium and iron atoms. The assumption is made that the observed broadened Zeeman sextets are superpositions of partial sextets corresponding to iron atoms with different nearest environments. The observed decrease in the hyperfine fields for the broadened sextets with an increase in the chromium content in the samples is in good agreement with a change in the concentration of the corresponding environments.  相似文献   
5.
This paper reports on the first study of the temperature and field dependences of the magnetization, heat capacity, and electrical properties of synthesized polycrystalline samples of aerugite Co10Ge3O16, as well as on x-ray diffraction analysis of this compound. It is shown that the cobalt ions in this compound occupy three nonequivalent positions. The results of the experimental and theoretical studies suggest that aerugite is a ferrimagnet with two uncompensated magnetic moments of the cobalt atom per formula unit.  相似文献   
6.
An approach is suggested to synthesize the ε-Fe2O3 particles supported on silica with the mean size of few nanometers, narrow size distribution and no admixture of any other iron oxide polymorphs. The facile synthesis is based on the pore filling impregnation method by iron sulfate (II) water solution with the following annealing procedure at ~1173 K. It is shown that the ε-Fe2O3 nanoparticles obtained are stable up to ~1173 K and possess superparamagnetic behavior up to ~870 K.  相似文献   
7.
The 2H(π?, π? p)n reaction is experimentally studied at 1 GeV/c for spectator neutron momenta up to 200 MeV/c. The spectator momentum and polar angle distributions and the Treiman-Yang angle distribution are in good agreement with theoretical calculations allowing for the diagrams in which the initial pion rescatters on the nucleons inside the deuteron not more than twice. We conclude that our understanding of the mechanism of the nucleon knock-out from a deuteron is correct. The simple example of the reaction on a deuteron confirms the possibility of describing direct processes with a small number of Feynman diagrams.  相似文献   
8.
This paper reports on the results of the synthesis and study of the diffraction patterns and M?ssbauer spectra of single crystals of homogeneous M xMn1 − x S solid solutions with a cubic NaCl structure prepared by the cation substitution of 3d elements for divalent manganese ions in manganese monosulfide. It has been shown that, similarly to the hydrostatic pressure, the substitution of 3d ions with a smaller ionic radius is accompanied by the contraction of the MnS cubic cell. The calculated lattice parameters agree with the experimental data. The homogeneous region of the formation of homogeneous solid solutions is limited in composition x, which depends on the choice of a substitutional cation.  相似文献   
9.
The effect of 0, 0.5, and 1?μm-thick Ag interlayers on the chemical interaction between Pd and Fe in epitaxial Pd(0?0?1)/Ag(0?0?1)/Fe(0?0?1)/MgO(0?0?1) and Fe(0?0?1)/Ag(0?0?1)/Pd(0?0?1)/MgO(0?0?1) trilayers has been studied using X-ray diffraction, 57Fe Mössbauer spectroscopy, X-ray photoelectron spectroscopy, and magnetic structural measurements. No mixing of Pd and Fe occurs via the chemically inert Ag layer at annealing temperatures up to 400?°C. As the annealing temperature is increased above 400?°C, a solid-state synthesis of an ordered L10-FePd phase begins in the Pd(0?0?1)/Ag(0?0?1)/Fe(0?0?1) and Fe(0?0?1)/Ag(0?0?1)/Pd(0?0?1) film trilayers regardless of the thickness of the buffer Ag layer. In all samples, annealing above 500?°C leads to the formation of a disordered FexPd1?x(0?0?1) phase; however, in samples lacking the Ag layer, the synthesis of FexPd1?x is preceded by the formation of an ordered L12-FePd3 phase. An analysis of the X-ray photoelectron spectroscopy results shows that Pd is the dominant moving species in the reaction between Pd and Fe. According to the preliminary results, the 2.2?μm-thick Ag film does not prevent the synthesis of the L10-FePd phase and only slightly increases the phase’s initiation temperature. Data showing the ultra-fast transport of Pd atoms via thick inert Ag layers are interpreted as direct evidence of the long-range character of the chemical interaction between Pd and Fe. Thus, in the reaction state, Pd and Fe interact chemically even though the distance between them is about 104 times greater than an ordinary chemical bond length.  相似文献   
10.
Amorphous ferrimagnetic Tb x Fe1?x films with perpendicular magnetic anisotropy and Tb x Fe1?x /NiFe exchange-coupled structures characterized by unidirectional anisotropy are obtained. The magnetic and chemical inhomogeneity of alloys of Tb x Fe1?x compensation composition is established on the basis of Mössbauer studies of these systems.  相似文献   
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