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Electronic structures of orthorhombic and monoclinic Cu4SnS4, which exhibit a first-order phase transition at 232 K, are demonstrated based on the generalized gradient approximation (GGA) of the density functional theory (DFT). The calculated band gap was 0.39 eV for orthorhombic phase, while that was not obtained for monoclinic one. These calculated results confirm monoclinic phase has smaller activation energy ( Ea) than orthorhombic phase. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

We have studied pressure effects on the magnetic and electronic nature of layered oxysulfide Sr2Cu2CoO2S2 which crystallizes in an unusual intergrowth structure. The derivative permeability (dμ/dT) curves have a kink near Tt at which the antiferromagnetic nature is changed from 2D to 3D; Tt extremely rises with increasing pressure (dTt/dP=13.5 K/kbar), indicating that 3D antiferromagnetic state is more stable under pressure. The Tt in the dμ/dT curves correspond to the bending point of the resistivity, and above Tt the nearest-neighbor hopping conduction occurs. These features would be discussed from the viewpoint of the coupled nature of charge carriers and 2D antiferromagnetic spin ordering. [Copyright &y& Elsevier]

We have studied the magnetic dilution and electronic nature of Zn doping on the Mn site in the colossal magnetoresistant material La0.7Pb0.3MnO3 (x≤0.3). Small non-magnetic Zn2+ doping tends to separate the system into ferromagnetic clusters to weaken the long-range ferromagnetic order and to reduce the Curie temperature. The spin polarizability of the x=0–0.3 samples is estimated to be 0.97–1.00, indicating that the x=0–0.3 samples are the spin polarized materials in which the conductivity is dominated by single-spin charge carriers. Small doping (x≥0.1) induces the metal–insulator transition and destroys the metallic state with long-range ferromagnetic order. [Copyright &y& Elsevier]

Electronic structures of orthorhombic and monoclinic Cu4SnS4, which exhibit a first-order phase transition at 232 K, are demonstrated based on the generalized gradient approximation (GGA) of the density functional theory (DFT). The calculated band gap was 0.39 eV for orthorhombic phase, while that was not obtained for monoclinic one. These calculated results confirm monoclinic phase has smaller activation energy ( Ea) than orthorhombic phase. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]