Diluted magnetic layered semiconductor InSe:Mn with high Curie temperature

We present a detailed study of layered semiconductor InSe doped with Mn. Xray and neutron diffraction analyses of (In,Mn)Se single crystals show the presence of a main phase as In₁−xMnxSe solid solution, the second antiferromagnetic MnSe phase, and traces of In₄ Se₃ Magnetic measurements reveal ferromagnetic behavior of (In,Mn)Se with the Curie temperature about 800 K. The ferromagnetic cluster model and exchange interaction via 2D electron gas, as the reasons of spontaneous magnetization, are discussed. The dramatic transformation of (In,Mn)Se electron spin resonance (ESR) spectra as a function of temperature is revealed. At the magnetic field perpendicular to crystallographic c axis, a low-field line within the temperature range 70 down to 4.7 K is observed. It shifts to smaller magnetic fields with temperature decrease. Neutron diffraction studies reveal the strong rise for one of the reflection peaks with temperature decrease in the same temperature region where ESR spectra transformation occurs. This peak corresponds to double MnSe interplanar distance in the [111] direction what is a period of its magnetic lattice. Magnetic structure of (In,Mn)Se single crystal is discussed

Electrodeposition of Co-Ni-MoxOy Powders: Part I. The Influence of Deposition Conditions on Powder Composition and Morphology

The Co-Ni-MoxOy powders were obtained electrochemically at a constant current density from ammonia electrolyte. Ni and Co were anomalously deposited, inducing Mo deposition, which cannot be deposited separately from aqueous solutions. The obtained Co-Ni-MoxOy powders were investigated by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and scanning electon microscope (SEM) methods. Based on the obtained experimental results, it was concluded that the particle size of deposited powders is influenced by the chemical composition of the electrolyte and current density imposed. XRD results suggested that obtained powders were of amorphous structure, although a Co3Mo compound can be formed if certain experimental conditions are applied

Interface magnetism in Fe-based nanocrystalline alloys

Nanoscale materials exhibit properties that can not be find in larger scale system due to the crystal size effects as well as structural variations between the interfacial regions and the crystalline interior. In this paper the consideration of the finite-size effects are limited to a special class of nonconventional granular materials produced by the devitritication of Fe-based amorphous ribbons. The complementary microstructural and magnetic studies show that in such mesoscopie systems the interfaces exhihit identifiable properties. The data presented do not provide the detailed picture of the internal structure of the boundary regions but bring information about their basic structural and magnetic properties. In particular the influence of the magnetic state of the intergranular amorphous matrix (ferroor paramagnetic) on the local magnetic behavior of the interfaces is considered. The effect of the symmetry restriction at grain boundaries on the structurally sensitive parameter such as a magnetostriction is also presented and discussed

Magnetic hyperfine fields in FeZrB amorphous alloys

FeZrB amorphous alloys with two different iron contents have been investigated by means of the Mössbauer spectroscopy over the temperature range 77-300 K. The thermal evolutions of spectral parameters are reported. The distributions of hyperfine fields, which show a bimodal profile, are simulated by two split Gaussian components and interpreted in terms of two different local environments of Fe atoms. One of them is identified with the exclusively Fe coordinated atoms, whereas the other is attributed to Fe atoms which have some Zr and B atoms as nearest neighbours