Magneto-resistance, thermal conductivity, thermo-electric power and specific heat of superconductor Gd_0.95Pr_0.05Ba₂Cu_2.94M_0.06O_7−δ (M=Fe, Ni, Zn and Mn)

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• 作者：Tirthankar Chakraborty^a ; Bhasker Gahtori^b ; Ajay Soni^c ; G.S. Okram^c ; S.K. Agrawal^b ; S.-Y. Chen^d ; Y.-K. Kuo^d ; M.A.H. Ahsan^e ; Ashok Rao^f ; ^{ashokanu_rao@rediffmail.com"" rel=""nofollow}
• 关键词：A. High ; none ; color ; black"" href=""/science?_ob=MathURL&_method=retrieve&_udi=B6TVW-52Y7D9K-1&_mathId=mml43&_pii=S0038109811002651&_issn=00381098&_acct=C000053662&_version=1&_userid=1553416&md5=c592805ba1d32b0a0
• 刊名：Solid State Communications
• 出版年：2011
• 出版时间：September 2011
• 年：2011
• 卷：151
• 期：17
• 页码：1117-1121
• 全文大小：822 K

文摘

In the present paper, we present thermal and electrical transport properties of pristine and co-doped samples of high temperature superconductors Gd_0.95Pr_0.05Ba₂Cu_2.94M_0.06O_7−δ. It is found that all the samples, except the Mn co-doped sample, show metallic behavior in the normal state. It is observed that the upper critical field has a correlation with the substituent site of the co-dopant. Thermal conductivity κ(T) of all the samples, except the one with Zn co-doping, exhibits a hump like structure around their respective transition temperatures. A negative sign of the measured thermo-power (S) in Gd-123 indicates that electron-like carriers dominate the heat transport in the pristine sample; whereas a sign reversal in S, as a consequence of the change of dominant carrier upon doping, is observed. Specific heat (C_P) measurements show a jump around the transition temperature (T_C) for the pristine sample, however, such a jump in C_P is strongly suppressed for the doped samples.