Solid Compounds of Transition Elements II

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Authors: Manjusha Inamdar, Martin Kriegisch, Lubuna Shafeek, A. Sidorenko, Herbert Müller, Andrey Prokofiev, Peter Blaha, Silke Paschen
Abstract: PtSn4 is a non-congruently melting compound in the Pt-Sn binary phase diagram, crystallizing in the centrosymmetric space group Ccca. We report on single crystal growth, temperature dependent electrical resistivity, isothermal field-dependent magnetization and magnetostriction, and on band structure calculations of this transition metal compound. The high quality of the sample makes it possible to observe clearly resolved quantum oscillations in the magnetization data for temperatures as high as 20 K and in magnetic fields as low as 10 kOe. We found several frequencies along the three crystallographic directions and could relate them to several extremal orbits on the Fermi surface.
Authors: Juan Bartolomé, Adriana Isabel Figueroa, Fernando Bartolomé, Luis Miguel García, Fabrice Wilhelm, Andrei Rogalev
Abstract: Metals which are non-magnetic in bulk form may present magnetism when shaped in reduced dimensions. Ag, Au, Pd and Pt nanoparticles have shown this behavior. They have in common an incompletely filled 4d (Au, Pd) or 5d-band (Au, Pt), that gives rise partially to this type of magnetism. By means of Xray Magnetic Circular Dichroism (XMCD) at the L2,3 edges the orbital and spin contributions to the magnetic moment stemming from the d-band has been explored. The different magnetic response of these metals, as viewed with XMCD, is revised.
Authors: Ryszard Zach, Janusz Toboła, Wieslaw Chajec, Daniel Fruchart, Fumihisa Ono
Abstract: Abstract. In this review paper comparison of magnetic properties in several MM’X-type intermetallics is presented. It may be summarized that main role in variation of magnetic interactions is played by modification of metallic sublattice in the tetrahedral but not in the pyramidal sites. It was shown not only in the case of composition, temperature and magnetic field dependencies but also by pressure variation of magnetic interactions. The latter was confirmed especially by electronic band structure calculations. Finally, in this report spin component and orbital one of magnetic moments for CoMnGe is presented for the first time.
Authors: Piotr Urbanowicz, Elzbieta Tomaszewicz, Tadeusz Groń, Henryk Duda, Slawomir Mazur, Zenon Kukuła, Sebastian Pawlus, Tadeusz Mydlarz, Józef Krok Kowalski
Abstract: Magnetic susceptibility measurements showed both a weak response to magnetic field and a lack of the Curie-Weiss region for CuEu2W2O10 and Cu3Eu2W4O18 tungstates characteristic for the multiplet widths comparable to thermal energy. Magnetization measurements displayed the linear temperature dependence with the lower magnetic moment for Cu3Eu2W4O18 in comparison with CuEu2W2O10, indicating that the effect of the electric charges associated with the surrounding ligands can change the multiplet width of individual states. It is affecting the electrical properties of examined tungstates which reveal the insulating state and low relative permittivity εr ~ 29 in case of CuEu2W2O10 and the thermally activated p-type electrical conduction for Cu3Eu2W4O18 with the activation energy of 1.11 eV and the large value of εr ~ 217 above the room temperature.
Authors: Dmitry Shulyatev, Mariya Lyange, Anna Pestun, Yakov M. Mukovskii, Eun Sang Choi, Alexey Suslov
Abstract: The influence of cation inhomogeneity on magnetic and electron transport properties of (La0.85Sr0.15)yMnO3 (y=0.92-0.97) single crystals were studied. It was found that both the temperature of ferromagnetic ordering TC and the temperature of orbital ordering TOO are increased with the Mn content decreasing. For all six samples studied two peaks on magnetoresistance curves were observed: the first near TC and the second close to TOO. The magnetic field does not affect the position of the former maximum, while it moves the latter towards lower temperatures.
Authors: Slawomir Mazur, Elzbieta Tomaszewicz, Tadeusz Groń, Henryk Duda, Zenon Kukuła, Tadeusz Mydlarz
Abstract: Magnetic susceptibility measurements revealed a disordered state of magnetic moments above 4.2 K for all compounds under study, and a weak response to the magnetic field and the temperature for Sm2W2O9 and Eu2W2O9 tungstates. The temperature independent component of magnetic susceptibility has a positive value for RE2W2O9 (RE = Pr, Nd and Gd) indicating a domination of van Vleck contribution. Only for Gd2W2O9 the magnetization is a universal function of µ0H/T, characteristic for the superparamagnetism.
Authors: Anastasya Shilova, Irina Chislova, V. Panchuk, V. Semenov, Irina Zvereva
Abstract: The present study is devoted to the non-isovalent substitution of Gd+3 for Sr+2 in matrix of Gd2-xSr1+xFe2O7 with perovskite-type intergrowth structure and to the investigation of oxidation state of iron depending on the method of synthesis and the content of solid solutions. Mössbauer spectroscopy showed the difference in the structure of complex ferrite Gd2SrFe2O7 obtained by ceramic technology (iron in single Fe+3 magnetically ordered state) from oxides obtained by the sol - gel technology (Fe+3 in the three different surroundings and presence of Fe+4).
Authors: Akyana Britwum, Tomasz Kolodziej, Waldemar Tokarz, Janusz Przewoźnik, Czesław Kapusta, Zbigniew Kąkol, Andrzej Kozłowski, Zbigniew Tarnawski, Jurgen M. Honig
Abstract: Magnetic field (up to 8T) and temperature (10-300K) dependence of size of Zn doped magnetite samples Fe3-xZnxO4 (x=0.008, 0.022, i.e. falling within first and second order Verwey transition regime) were measured by the strain gauge method. Both samples experienced shrinking on cooling through the Verwey transition along monoclinic c axis, while the strong expansion was found for the 1st order sample in the a-b direction, unlike in the 2nd order sample. Magnetostriction of both samples is very small and limited to low fields only, concomitant with magnetization process. However, field application perpendicular to c axis and at T slightly below the Verwey transition temperature TV results in a large change of dimensions, coinciding with the axis switching process.
Authors: Peediyekkal Jayaram, T.P. Jaya, P.P. Pradyumnan
Abstract: This work reports the synthesis of novel quaternary transparent conducting oxide Cd(1-x)Sn(1-x)InxGaxO3( x=0.1, 0.2, 0.3) at 1225°C via solid state reaction route. The investigations on structural, optical and electrical properties have been carried out. Powder X-ray diffraction revealed the phase purity and distorted orthorhombic structure of the species synthesized. Distortion of the structure is due to the substitution of In3+ and Ga3+ in CdSnO3 (JCPDS card no.340885) matrix. The optical transmittance approximated by the reflectance shows considerable increase in the transmittance of visible light along with the increase of substitution. Typical Burstein-Moss effect is observed with the increase in x value as a variation in optical bandgap from 2.7 to 2.9eV. Four point Hall measurements by Van der-Pauw method exhibit superior properties in charge carrier concentration and mobility. Maximum bulk charge concentration of 4.78x1017 cm-3 is obtained for x=0.3. Hall mobility depends on carrier concentration and steeply increases with the carrier concentration. Considerable drop in the resistivity of the material along with higher transmittance is a critical finding in the experiment.
Authors: Kwong Kau Tiong, Cheng Hsien Lin, Yi Min Chen, Ying Sheng Huang, Kuei Yi Lee, Dah Shyang Tsai
Abstract: Large surface area nanostructural IrOx films were deposited on stainless steel substrates by reactive radio frequency magnetron sputtering using Ir metal target. The structural and spectroscopic properties of the nanostructural IrOx were characterized. The micrographs of field emission scanning electron microscopy showed the formation of folded leaves with chiffon-like structure for the as-deposited samples. X-ray photoelectron spectroscopy analysis provided the information of the oxidation states and the stoichiometry of IrOxNL. Raman spectra revealed the amorphous-like phase of the as-deposited nanostructural IrOx. The chiffon-like structure provides ultra-high surface area for electrical charge storage which makes the IrOxNL as an attractive candidate for the supercapacitor application.

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