• G R Myneni

Articles written in Pramana – Journal of Physics

• Thermal conductivity of large-grain niobium and its effect on trapped vortices in the temperature range 1.8–5 K

Experimental investigation of the thermal conductivity of large grain and its dependence on the trapped vortices in parallel magnetic ﬁeld with respect to the temperature gradient $\nabla T$ was carried out on four large-grain niobium samples from four different ingots. The zero-ﬁeld thermal conductivity measurements are in good agreement with the measurements based on the theory of Bardeen–Rickayzen–Tewordt (BRT). The change in thermal conductivity with trapped vortices is analysed with the ﬁeld dependence of the conductivity results of Vinen et al for low inductions and low-temperature situation. Finally, the dependence of thermal conductivity on the applied magnetic ﬁeld in the vicinity of the upper critical ﬁeld $H_{c2}$ is ﬁtted with the theory of pure type-II superconductor of Houghton and Maki. Initial remnant magnetization in the sample shows a departure from the Houghton–Maki curve whereas the sample with zero trapped ﬂux qualitatively agrees with the theory. A qualitative discussion is presented explaining the reason for such deviation from the theory. It has also been observed that if the sample with the trapped vortices is cycled through $T_c$, the subsequent measurement of the thermal conductivity coincides with the zero trapped ﬂux results.

• # Pramana – Journal of Physics

Current Issue
Volume 93 | Issue 6
December 2019

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019