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

The temperature dependences of the resistivity ρ, magnetoresistance Δρ/ρ, heat conductivity κ and Seebeck effect S of La0.7Ca0.3Mn1–y GeyO3–δ (0 < y < 0.14) fixed valence doped compounds were studied between 50 K and 325 K using the 4-point and time resolved thermoelectric effect (TTE) methods. Curie temperature Tc and conductivity first decrease with y and then go up again. ... إقراء المزيد

he J-E characteristics, dc conductivity and thermoelectric power (TEP) measurements have been carried out on the bulk amorphous Ge14Se 86-xTlx, samples as a function of composition (x = 22, 23.5, 25 & 28 mole %) and temperature (240-420 K). In general, the J-E characteristics are linear for lower voltages and become non-linear at higher voltages. DC conductivity is found to ... إقراء المزيد

SUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 BA0.5 Y0.3CUOX POWDER COMPACTSSUPERCONDUCTING PROPERTIES OF K0.2 ... إقراء المزيد

The temperature dependences of the resistivity r and the heat conductivity k of La Ca Mn Fe O (0,x,0.12) fixed valence 0.7 0.3 12x x 32d doped crystals were studied between 50 and 340 K using the time resolved thermoelectric effects (TTE-method). The heat conductivity k is dominated by the lattice contribution and changes from a crystalline to a randomized ... إقراء المزيد

THE ENERGY GAP IN BI2-X PBXSR2CA2CU3OY SUPERCONDUCTORS WITH X (0.00£ X £0.50).THE ENERGY GAP IN BI2-X PBXSR2CA2CU3OY SUPERCONDUCTORS WITH X (0.00£ X £0.50).THE ENERGY GAP IN BI2-X PBXSR2CA2CU3OY SUPERCONDUCTORS WITH X (0.00£ X £0.50).THE ENERGY GAP IN BI2-X PBXSR2CA2CU3OY SUPERCONDUCTORS WITH X (0.00£ X £0.50).THE ENERGY GAP IN BI2-X PBXSR2CA2CU3OY SUPERCONDUCTORS WITH X (0.00£ X £0.50).THE ENERGY GAP IN BI2-X ... إقراء المزيد

The temperature dependences of the thermoelectric power, TEP, (S) and magnetoresistance (MR) effect of La1-xLixMnOy (x = 0.05, 0.1, 0.15, 0.2 & 0.25 at %) fixed valence doped compounds were studied between 80K and 320K. X-ray powder diffraction (XRD) showed that the samples are single phase. We found the correlation of structures to the mag-netoresistance (MR) and the thermoelectric power ... إقراء المزيد

The temperature dependences of the magnetization M; the resistivity r, the heat conductivity k and the thermoelectric power S of La0.7Ca0.3Mn1yGeyO3 (0oyo0:20) fixed valence doped crystals were studied between 50 and 340 K, k and S using time-resolved thermoelectric transients. The results are discussed in terms of Zener bond blocking via single and pair fixed valence sites Ge+4 إقراء المزيد

The occurrence of a large positive and negative magnetoresistance (±MR) in mixed magnetically coupled and weakly lattice-coupled spin systems is discussed and compared with an experimentally observed example of GMR in manganites R1-xExMnO3-δ, i.e., oxygen deficient La0.7Ca0.3MnO3-δ. We indeed find even some of the more capricious features of the MR reproduced by experiment and the condition that the metal-insulator (Tmi) ... إقراء المزيد

Using the transient thermoelectric effect (TTE), we have measured the thermoelectric power SðTÞ and the heat conductivity kðTÞ of La1xSrxMnO3 ceramic surface layers with nominal compositions x ¼ 0:075; 0.1, 0.15, 0.2 and 0.3 in the temperature range 50–340 K. Except for a shift in the characteristic temperatures, the surface layer SðTÞ is still similar to the bulk thermopower while ... إقراء المزيد