A. Winiarski

X-ray photoemission spectra of La0.7Sr0.3MnO3 perovskite

Abstract X-ray photoemission (XPS) measurements of the core levels and valence electronic structure of La0.7Sr0.3MnO3 are presented. The ferromagnetic phase La0.7Sr0.3MnO3 is half-metallic, which is important in the relation to colossal magnetoresistance properties of this compound. Comparing XPS measurements, and the LMTO band-structure calculations for La0.75Sr0.25MnO3, one concludes that the electronic structure of La0.7Sr0.3MnO3 compound consists mainly Mn 3d and O 2p states. In addition, the Mn 3d and O 2p states are hybridized over whole valence band. States of 3d character localized in Mn site predominate near the top of the valence band.

Magnetism of manganese in and (R = Y, Gd, Er) intermetallics

The XPS electronic structure was measured for , and single crystals and pure Mn. Exchange splitting of Mn 3d and 3s states was found for the compounds with magnetic manganese. The electrical resistivity of the single crystal shows an antiferromagnetic transition at 108 K and the second transition at 32 K. The lattice parameter against temperature of exhibits a large spontaneous magnetostriction at . The anisotropic character of the magnetization was found. The results were discussed using the Yamada and Shimizu model.

Crystal structure, magnetic and electrical properties of YFe4Al8 single crystals

Abstract Single crystals of YFe 4 Al 8 were obtained by the Czochralski method from a levitated melt. Their quality was checked by the Berg-Barrett and Laue methods. The electrical resistivity and the magnetic susceptibility were studied. Besides the antiferromagnetic transition at 195 K, weak ferromagnetism was observed below 100 K.

Electronic structure of La0.65Pb0.35MnO3 perovskite studied by X-ray photoemission spectroscopy

Abstract The electronic structure of La 0.65 Pb 0.35 MnO 3 has been studied by X-ray photoemission spectroscopy (XPS). The valence band spectrum is compared with ab-initio electronic structure calculations using linearized muffin–tin orbital (LMTO) method. The XPS measurements, and the theoretical band-structure calculations for La 0.75 Pb 0.25 MnO 3 , show that the electronic structure of La 0.65 Pb 0.35 MnO 3 compound consists mainly of Mn 3d and O 2p states. In addition, the Mn 3d and O 2p states are hybridized over the whole valence band. States of 3d characters localized in Mn site predominate near the top of the valence band. We have found a good agreement between the experimental valence band spectra and theoretical calculations.

Crystal growth of R3Ni intermetallic compounds by Czochralski method from a levitated melt (R = Y, Gd, Tb, Dy, Ho, Er)

Abstract Single crystals of R 3 Ni (for R = Y, Gd, Tb, Dy, Ho, Er) were obtained by the Czocharlski method from a levitated melt. The X-ray methods were used for examination of the real structure.

Magnetic properties of the TbMn2 single crystals

Abstract Single crystals of TbMn 2 were grown by the Czochralski method from a levitated melt. Results of electrical resistivity, magnetization in strong magnetic fields along the principal crystallographic directions, AC and DC magnetic susceptibility and the temperature dependence of the lattice parameter are presented.

Electronic structure and magnetic properties of HoMn2 single crystals

Abstract Single crystals of the HoMn 2 compound were grown by the Czochralski method from a levitated melt. The thermal dependence of the electrical resistivity exhibits a magnetic transition at 29 K. A second transition occurs at 21 K. Moreover, for ρ ( T ) a T 2 dependence at low temperatures and saturation effects above 250 K were found. The magnetization in strong magnetic fields and the DC and AC magnetic susceptibilities measured along the principal crystallographic directions show ordering of the holmium moments to a spin-canted magnetic structure at about 25 K and a spin reorientation below 21 K.

Growth of Fe3−xVxAl

Abstract Single crystals of Fe 3−x V x Al, for x = 0.5, 0.75 and 1, were obtained by the Czochralski method from a levitated melt. For comparison growth of the Fe 2.5 V 0.5 Al alloy was performed by the Bridgman method in an alundum crucible. X-ray diffraction methods were used to study real structure of the crystals. The crystals obtained from levitation have much better quality than the one from the crucible method and are homogeneous and free from strains. The quality of the samples with higher vanadium content becomes worse.

Properties of Y3Rh and Y3Ir

Abstract Electrical resistivity, magnetic susceptibility, lattice parameters and XPS valence band were measured for Y 3 Rh and Y 3 Ir single crystals. The electrical resistivity shows T 2.5 dependence up to 40 K for Y 3 Rh and 45 K for Y 3 Ir, next the inflection point and the pronounced negative curvature and finally the tendency to saturate at higher temperatures. The magnetic susceptibility obeys the Curie-Weiss law after subtracting the temperature independent term χ 0 . For Y 3 Rh μ eff = 0.7 μ B and Θ = −13 K , for Y 3 Ir μ eff = 0.84 μ B and Θ = 5 K . The lattice parameters show an anomalous variation with temperature. The XPS valence band measurements exhibit a single narrow state of 4d rhodium or 5d of iridium, the top of which may be hybridized with the bottom of 4d states of yttrium. This effect may be responsible for the mentioned phenomena.