Yazar "Kolat V.S." seçeneğine göre listele

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    Magnetocaloric behaviour in Fe57Cr17Cu 1Nb3Si13B9 soft magnetic alloys
    (2004) Kolat V.S.; Atalay S.
    In this study, the magnetocaloric effect in as-received and nanocrystalline Fe57Cr17Cu1Nb 3Si13B9 alloys in ribbon form was investigated The temperature dependence of the magnetic entropy variation, ?S m, was calculated from the magnetisation data. It was found that the Curie temperature of the as-received amorphous sample is 156 K and the maximum entropy change occurs at this temperature. The calculated value of the maximum entropy change under 6 T magnetic field is about 1 J/kg.K in as-received amorphous ribbon and 1.12 J/kg.K for nanocrystalline sample under 5 T magnetic field. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Öğe
    Magnetotransport and magnetoresistance properties of Pr 0.68Ca0.32-xSrxMnO3 (x= 0, 0.1, 0.18, 0.26 and 0.32) manganites
    (National Institute of Optoelectronics, 2011) Izgi T.; Kolat V.S.; Bayri N.; Kaya A.O.; Gencer H.; Atalay S.
    In this study, the magnetotransport and magnetoresistance properties of Pr0.68Ca0.32-xSrxMnO3 (x= 0, 0.1, 0.18, 0.26 and 0.32) compounds were investigated. The system illustrate an evolution from a charge-ordered manganite at x = 0, with an insulating-like resistivity and low magnetization values, towards to a completely ferromagnetic metallic state for x = 0.32. Above the metal-insulator transition temperature TMI, the resistance curves were fitted to the small polaron popping model. The activation energy (Ea) was found to decrease with increasing Sr content. In the phase separated (PS) state, due to the coexistence of ferromagnetic (FM) metallic and charge order (CO) insulating phases, the magnetoresistance (MR) was found to be maximum. The MR ratio of 6.3x10 8 for the sample x = 0 at 60 K is one of the largest MR change has been reported in manganites. The MR values decreases considerably with increasing Sr content and the activation energy decreases with the increase of Sr content.