Magnetic,dielectric, and transport properties of bismuth pyrostannate Bi2(Sn0.9Mn0.1)2O7

Physics of the Solid State - The effect of replacing manganese ions on the structural, dielectric, transport, and magnetic properties of Bi2(Sn0.9Mn0.1)2O7 has been studied and the correlation...     

Magnetic and electrical properties of cation-substituted sulfides MexMn1 ? xS (Me = Co, Gd)

The temperature dependences of the specific magnetization σ and the electrical resistivity ρ of Me _x Mn_{1 − x} S single crystals (Me= Co, Gd; x= 0.05) have been studied in the temperature range 80 K < T < 1000 K. The samples under study have revealed the presence of a spontaneous magnetic moment below the Néel temperature (T _N) and ferromagnetic clusters in Gd_0.05Mn_0.95S in the temperature range 146 K < T < 680 K. Substitution of gadolinium for manganese initiates a transition from p-type to n-type conduction. The change in the conduction type is accompanied by an increase in the electrical resistivity at 300 K by approximately one order of magnitude and, accordingly, by a decrease in the activation energy. The magnetic and electrical properties of the crystals under study have been interpreted in terms of the cluster model with temperature-dependent ferromagnetic exchange and an electron localized in this cluster. Original Russian Text ? S.S. Aplesnin, L.I. Ryabinkina, O.B. Romanova, V.V. Sokolov, A.Yu. Pichugin, A.I. Galyas, O.F. Demidenko, G.I. Makovetskiĭ, K.I. Yanushkevich, 2009, published in Fizika Tverdogo Tela, 2009, Vol. 51, No. 4, pp. 661–664.     

Low-temperature metal-insuslator transition and magnetic properties in the VxMn1−x S disordered system

A study of the structure and electrical and magnetic properties of the V_xMn_1−x S disordered system is reported. The existence of a low-temperature metal-insulator transition for Fermi-glass 0.4<x<0.5 compositions in paramagnetic phase, which is accompanied by a change in the structure and magnetic properties, has been established. An analysis of the magnetic properties permits a conjecture that current carriers become delocalized in these solid solutions at the metal-insulator transition temperature to form small ferromagnetically ordered regions (ferrons). Fiz. Tverd. Tela (St. Petersburg) 39, 1428–1431 (August 1997)     

Correlation between the magnetic and electrical properties of MnSe1-x Te x chalcogenides

The coefficients of thermal expansion, lattice constant, and magnetization of anion-substituted MnSe_{1 - x}Te_x chalcogenides were measured upon cooling in zero and nonzero magnetic fields in the temperature range 4.2–600 K. Resistivity as a function of magnetic field up to 1 T was measured. The dynamic properties of the materials were studied by the ESR method. Magnetoresistance and temperature hysteresis were found in MnSe_{1 - x}Te_x solid solutions.     

Magnetic properties and the metal–insulator transition in GdXMn1−XS solid solutions

The structural, magnetic, electrical, and thermoelectric properties of Gd_XMn_1?XS ($0.01\le X\le 0.3$) solid solutions synthesized for the first time on the basis of $\alpha$-MnS have been studied experimentally in the temperature range 77–1000 K in magnetic fields up to 10 kOe. The synthesized samples are antiferromagnetic semiconductors with an NaCl-type cubic lattice typical of $\alpha$-MnS. Both concentration ($X_c=0.3$) and temperature ($T_c=450K$) metal–insulator phase transitions have been observed. The concentration metal–insulator transition is accompanied by a decrease in resistivity and thermopower by twelve and two orders of magnitude, respectively, with the change in conductivity from p-type to n-type.     

Electrical conductivity and thermopower in Co<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> Mn<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript> S sulfides

This paper reports on the results of investigations into the structural, electrical, and thermoelectrical properties of sulfides Co _x Mn_{1 ? x} S (0 ≤ x ≤ 0.4) in the temperature range 80–950 K. It is established that the thermopower coefficient α decreases significantly with an increase in the cobalt concentration in the lattice of the α-MnS compound. The Co _x Mn_{1 ? x} S compounds with cobalt concentrations in the range 0 ≤ x ≤ 0.3 are semiconductors with hole conduction (α > 0), whereas the compound with x = 0.4 exhibits metallic conduction (α < 0). It is found that the band gap E _g of the compounds under investigation varies in the range from 1.46 eV for α-MnS (x = 0) to 0.26 eV for Co _x Mn_{1 ? x} S (x = 0.4).     

Correlation of the magnetic and transport properties with polymorphic transitions in bismuth pyrostannate Bi2(Sn1 − x Cr x )2O7

Physics of the Solid State - The correlation of the electrical, magnetic, and structural properties of Bi2(Sn1 − x Cr x )2O7 solid solutions has been investigated for two compositions with x...     

Electrical Properties of the Polycrystalline BiFe0.95Co0.05O3 Films

Physics of the Solid State - Semiconductor BiFe0.95Co0.05O3 thin-film compounds have been synthesized by a burst technique. The film surface morphology and the effect of electronic doping via...