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    Magnetic and electrical properties of La0.67Ca0.33Mn0.9V0.1O3 two-phase composite
    (Elsevier, 2006) Kolat, VS; Gencer, H; Atalay, S
    In this work, we present magnetic and electrical properties of La0.67Ca0.33Mn1-xVxO3 (x=0 and 0.1). Polycrystalline La0.67Ca0.33MnO3 and La0.67Ca0.33Mn0.9V0.1O3 samples were prepared by conventional solid-state reaction. Two Curie temperatures for the La0.67Ca0.33Mn0.9V0.1O3 sample were observed at T-c1 = 223 K and T-c2 = 190 K. The undoped La0.67Ca0.33MnO3 sample showed only one magnetic transition temperature at 267K. The temperature dependence of resistance showed two maxima in the V-doped sample, and the peak value of magnetoresistance (MR) around the Curie temperature increased with V doping. Double maxima ill the resistance-temperature and magnetisation-temperature Curves are explained by the existence of two phases ill La0.67Ca0.33Mn0.9V0.1O3 samples. (c) 2005 Elsevier B.V. All rights reserved.
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    Magnetic entropy change in Fe74-xCrxCu1Nb3Si13B9 (x=14 and 17) amorphous alloys
    (Elsevier Science Bv, 2005) Atalay, S; Gencer, H; Kolat, VS
    In this study, the magnetic entropy variation in Fe74-xCrxCu1Nb3Si13B9 (x = 14 and 17) amorphous alloys was investigated. The temperature dependence of the magnetic entropy variation was calculated from the magnetization data. It was found that the Curie temperature of the sample decreases with increasing Cr content. The maximum entropy change corresponding to a magnetic field variation of 3 T is about 0.9 J/kg K for Fe60Cr14Cu1Nb3Si13B9 and 0.6 J/kg K for Fe57Cr17CU1Nb3Si13B9. (c) 2005 Elsevier B.V. All rights reserved.
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    Magnetocaloric effect in the La0.62Bi0.05Ca0.33MnO3 compound
    (Elsevier, 2005) Gencer, H; Atalay, S; Adiguzel, HI; Kolat, VS
    Bi-doped lanthanum manganite with chemical composition of La0.62Bi0.05Ca0.33MnO3 has been prepared by the standard solid-state process. The effect of Bi doping on the sintering temperature, the magnetic and magnetocaloric properties has been investigated. Bi2O3 was found to be an effective sintering aid for La0.67Ca0.33MnO3. It was found that small amounts of Bi doping (x = 0.05) can lower the sintering temperature about 200 degrees C. Bi-doped samples also exhibited a large magnetic entropy change, vertical bar Delta S-m vertical bar 3.5 J/kg K under 1 T field at the Curie temperature. (c) 2004 Elsevier B.V. All rights reserved.
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    The range of exchange interactions and curie temperature in La0.67-xBixCa0.33MnO3 compounds
    (World Scientific Publ Co Pte Ltd, 2005) Gencer, H; Atalay, S
    Magnetic properties of Bi-3+-doped La0.67-xBiXCa0.33MnO3 (x = 0, 0.05, 0.1, 0.2) are investigated. Using the mean-field and ferromagnetic spin-wave theory at low temperatures, total exchange integrals and Curie temperatures are calculated in the range 0 <= x <= 0.2. Calculated values of T,, are in good agreement with those obtained by magnetic measurements. In addition, the total exchange integral decrease with Bi3+ shows the existence of canted ferromagnetic order in the samples, as observed in experimental results.