3 research outputs found
Analysis of Experimental Conditions for Simultaneous Measurements of Transport and Magnetotransport Coefficients of High Temperature Superconductors
Experimental conditions for simultaneous measurements of transport
coefficients of high temperature superconductors in zero and non-zero magnetic
fields are analysed. Test measurements of the thermal conductivity, the
thermoelectric power and the Nernst - Ettingshausen effect of a textured Bi2212
sample are reported in an external magnetic field of 2T. Errors related to
parameters of the thermocouple used and to the spurious heat flows are
discussed for a new experimental set-up built based on a closed cycle helium
refrigerator. Possible optimising of experimental conditions is suggested.Comment: 9 pages + 4 figures. accepted for publication in Cryogenic
Magnetocaloric effect in La<inf>0.75</inf>Sr<inf>0.25</inf>MnO<inf>3</inf> manganite
The polycrystalline manganite La0.75Sr0.25MnO 3 prepared by an alternative carbonate precipitation route reveals the rhombohedral perovskite structure. Magnetization isotherms measured up to 2 T are used to determine Curie temperature of 332 K by means of Arrott plot. Maximum of magnetic entropy change is found at Curie temperature. The relative cooling power equal to 64 J/kg for 1.5 T magnetic field, is superior as compared to the manganite with the same chemical composition from the solgel method. © 2010 Elsevier B.V. All rights reserved
Magnetic susceptibility and electron magnetic resonance study of monovalent potassium doped manganites Pr<inf>0.6</inf>Sr<inf>0.4-x</inf>K <inf>x</inf>MnO<inf>3</inf>
The monovalent potassium doped manganites Pr0.6Sr 0.4-xKxMnO3 (x = 0.05-0.2) are characterized using the complementary magnetic susceptibility and electron resonance methods. In paramagnetic phase the temperature variations of the inverse magnetic susceptibility and the inverse intensity of resonance signal obey the Curie-Weiss law. A similarity in temperature variation of resonance signal width and the adiabatic polaron conductivity points to the polaron mechanism controlling the resonance linewidth. The low temperature limit of the pure paramagnetic phase is determined from the electron resonance spectra revealing the mixed phase spread down to the Curie temperature. © 2013 Elsevier B.V. All rights reserved