M. Kulpa

Electronic structure of La 3d in gallate and aluminate single crystals

Abstract An investigation of the 3d X-ray photoelectron spectra of lanthanum in LaGaO3, SrLaAlO4, SrLaGaO4 and SrLaGa3O7 is reported. The splitting of La 3d spectra is found to be more complicated that has been previously reported. The energy separation of the doublet structure 3d 94f0L and 3d 94f1 L decreases with the decrease of coordination number of the La ion.

Electronic structure, magnetic and electrical properties of Fe3−xVxAl compounds

Abstract The electronic band structure, magnetic and transport properties of monocrystalline Fe3−xVxAl compounds with the B2-type structure were investigated. It was found that the magnetic and unusual transport properties are due to a strong hybridization of the 3d states of iron and vanadium and their shift to below the Fermi energy.

Magnetic properties of DyMn2 single crystals

Abstract Single crystals of the DyMn 2 compound were grown by the Czochralski method from a levitated melt. The electrical resistivity exhibits a magnetic transition at 40 K, a second transition at 25 K, a cubic temperature dependence at low temperatures and a saturation effect above 250 K. The magnetization in strong magnetic fields, and the DC and AC magnetic susceptibility measured along the principal crystallographic directions show an ordering of the dysprosium moments to a spin-canted magnetic structure at about 40 K and a spin reorientation below 25 K. The temperature dependence of the lattice parameter shows a lattice contraction below 40 K.

Magnetic properties of ErMn2 single crystals

Abstract Single crystals of the ErMn 2 compound were grown by the Czochralski method from a levitated melt. The thermal dependence of the lattice parameters exhibits a magnetovolume effect along the a axis, a contraction for both the c axis and unit cell volume below 20 K. The thermal dependence of the electrical resistivity exhibits a magnetic transition at 23 K. A second transition occurs at 13 K. Moreover, for ρ ( T ) a negative curvature above the ordering temperature and a saturation effect above 200 K occurs. The magnetization in strong magnetic fields, the d.c. and a.c. magnetic susceptibilities measured along the principal crystallographic directions show ordering of the erbium moments to a spin-canted magnetic structure at about 15 K and a spin reorientation about 10 K.

Electronic structure of TbMn2 and DyMn2 single crystals

Abstract Electronic structure measurements of TbMn2 and DyMn2 single crystals were performed at room temperature using the X-ray photoelectron spectrometer. In the valence band of TbMn2 a gathering of the Mn 3d states at the Fermi level was observed much stronger than that one found for DyMn2. This structure observed in the valence band for TbMn2 may indicate on the splitting Mn 3d band of TbMn2 and results in a huge magnetovolume anomalies at low temperatures like for YMn2.

On the new ternary gadolinium silver aluminide GdAgAl

Abstract The compound GdAgAl which crystallizes in the orthorhombic CeCu2-type structure was prepared. Spin glass behaviour was observed at low temperatures. At high temperatures, the magnetic susceptibility obeys the Curie–Weiss law. Disorder of the nonmagnetic atoms sublattice leads to high electrical resistivity value what influences the magnetic ordering.

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.