Effect of Ni doping on the thermal expansion of the high- superconductor

Abstract

Thermal expansion measurements have been carried out for the Ni-substituted compounds with a high-resolution dilatometer using the three-terminal capacitance technique. The present set-up is sensitive enough to detect changes in of less than . Results indicate that the jump in the coefficient of linear thermal expansion decreases with increase in Ni content. For x = 1.5%, decreases by a factor of 3 whereas does not change appreciably. There is evidence that the temperature dependence of for compounds with high Ni concentration depends on the conditions of sample growth.

Effect of Fe, Co, and Zn Substitution on Thermal Expansion of GdBa[sub 2]Cu[sub 3]O[sub 7]

“…It is seen that the jump in thermal expansion decreases with increase in Zn content. Similar trend is seen in Zn and Ni doped samples of YBaCuO samples [1,6]. From figures 3 and 4, we observe that a increase in jump is observed in jump in thermal expansion for dopants which occupy the Cu(2) site.…”

Effect of Mn doping on the specific heat of the highTCsuperconductor REBa2Cu3Oy(RE = Y,Gd)

“…Several investigators have carried out substitution experiments in high T C superconductors, which has helped further understanding of the mechanism of superconductivity as well as improving the magnetic properties, like flux pinning etc, in order to enhance the applicability of these materials. In particular, substituting transition metal elements, for example Zn, Fe, Ni and Co, for Cu dramatically affects the superconducting and normal state properties [1][2][3][4][5][6][7][8]. Different impurities have preferential occupancies due to the presence of two copper sites in these high T C superconductors, a plane and a chain.…”

“…Dopants like Fe and Co occupy plane sites with an accompanying orthorhombic to tetragonal structural transformation [1][2][3]. However no such transformation is observed for Zn and Ni that occupy chain sites [4][5][6][7][8]. The structural transformation leads to corresponding variations in the physical properties, such as the lattice components of specific heat, the coefficient of thermal expansion and the pressure dependence of the transition temperature, dT C /dP.…”

Electrical and thermal transport properties of EuBa2(Cu1−xMnx)3O7−δ

“…There are a number of reports on partial and full substitution effects in high T C superconductors and such substitutions in general, found to have an influence on the superconducting as well as normal state properties [1][2][3][4][5][6][7][8]. The primary aim of such studies is to rationalize the underlying mechanism behind the principle of superconductivity by altering the composition of these compounds.…”