The temperature dependence of the resistivity (ρ) and magneto-resistance (MR) effect of La1−xLixMnOy (x = 0.05, 0.1, 0.15, 0.2 & 0.25 at.%) fixed valence doped compounds were studied between 80 and 320 K. X-ray powder diffraction (XRD) at room temperature shows that the samples are single phase. The resistivity of all samples with and without magnetic field shows a metal–semiconductor ... إقراء المزيد

The electrical properties of sintered compacts of BiSnSe2. إقراء المزيد

The effect of Na doping and annealing time on the structure, electrical properties, magnetoresistance and thermopower properties has been investigated in perovskite La1xNaxMnOy (x ¼ 0.025, 0.075 and 0.1) systems. La1xNaxMnOy crystallizes in a single-phase rhombohedral structure. It is observed a simultaneous occurrence of the ferromagnetic to paramagnetic state and metallic to insulating state. In the meanwhile, a large negative ... إقراء المزيد

The thermoelectric power and Hall measurement carried out on the asprepared sample of Ga0.45 In0.55 Sb confirmed that the sample is n-type semiconductor. The existence of two minima at 3.5 and 4.8 Vcm-1 on the σ - E characteristic reflects the occurrence of the Gunn effect. A metallic like behavior of the sample is observed and interpreted. The effect of ... إقراء المزيد

Vacuum heat treatment effects at 850 C for (3, 6, 9 and 12 h) on the crystalline structure and superconducting, as well as on the mechanical properties of Bi4Sr3Ca3Cu6Ox (BSCCO) have been studied. The highest critical transition temperature Tc 102 K was achieved at annealing time tann = 9 h. This maximum value is attributed to movement of excess oxygen ... إقراء المزيد

Chalcogenide glasses with Ge10As_x_Te90−_x_ (_x_ = 20, 25, 30, 35, 40, 45 and 55 at.%) were prepared by melt quenching technique. The glass transition temperature, the crystallization temperature, the melting temperature and the glass-forming tendency were determined from the differential scanning calorimetry measurements. The structural and optical properties of Ge10As_x_Te90−_x_ thin films prepared by electron beam evaporation were studied. X-ray ... إقراء المزيد

The crystal structure, electrical resistivity (r), magnetoresistance (MR) and Seebeck coefficient (S) of La1xNaxMnOy (x ¼ 0:075, 0.1, 0.125,0.15, and 0.175 at%) are investigated. La1xNaxMnOy crystallizes in a single-phase rhombohedral structure. The temperature dependence of the resistivity with and without magnetic field shows a metal–semiconductor transition at Tm, which depends on the Na content. We determine the activation energy Er ... إقراء المزيد

ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF GE40TE60 AND GE38SN2TE60 ALLOYS.ELECTRICAL CONDUCTIVITY AND THERMOELECTRIC POWER OF ... إقراء المزيد

Chalcogenide bulk alloys of Agx (As0.4Se0.6) 100Kx (xZ5, 7.5, 10, 12.5, 15 and 17.5) system were prepared by the conventional meltquench technique. The d.c. electrical conductivity (s) and thermoelectric power (TEP) measurements were carried out in the temperature range from 83 to 373 K and from 253 to 373 K, respectively. Variations of both s and TEP with ambient temperature ... إقراء المزيد

DC electrical resistivity (r) and thermoelectric power (TEP) of La0.7xBixSr0.3MnOy (x=0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 at%) manganites have been studied. The resistivity of the samples shows a metal–semiconductor (insulator) transition for xX0.2. For x=0.25 and 0.3 at%, the compounds exhibit semiconducting behavior down to T=83 K. The TEP for xp0.2 at% is of positive sign above the ... إقراء المزيد