Research Article
Investigation of Vortex Dynamics in Bi-2212 Superconductor Using Third Harmonic Ac Magnetic Susceptibility Superposing High Dc Magnetic Field
D. Paladhi, RC. Sahoo, TK. Nath
Correspondence Address :
TK. Nath
Department of
Physics, Indian Institute of Technology Kharagpur, West Bengal
721302, India
Email: tnath@phy.iitkgp.ernet.in,
tapnath@gmail.com
Received on: July 22, 2017, Accepted on: December 25, 2017, Published on: January 05, 2018
Citation: D. Paladhi, RC. Sahoo, TK. Nath (2018). Investigation of Vortex Dynamics in Bi-2212 Superconductor Using Third Harmonic Ac Magnetic
Susceptibility Superposing High Dc Magnetic Field
Copyright: 2018 TK. Nath, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Abstract
We have investigated the vortex dynamics of high quality single phase polycrystalline Bi2Sr2Ca1Cu2O8+δ (Bi-2212) high Tc superconductor using dc magnetization and ac magnetic susceptibility measurements up to magnetic field of 45 kOe. We have mainly used third harmonic signal (χ3) in the ac susceptibility technique to analyze the vortex dynamics in the sample since third harmonic signal gives nonlinear magnetization and can be measured in zero dc magnetic field. High quality single phase samples with superconducting transition temperature (Tc) 70 K have been prepared by standard solid state reaction method. We have shown that the inter-grain characteristics affect the magnetic property efficiently inside a superconductor in high dc magnetic field. Isothermal field dependent magnetization shows reversible behavior at temperatures close to the Tc. A sudden rise in χ3 has been observed at low temperature when the applied superimposed dc magnetic field is of 6.0 kOe or above. The low temperature state seems to be re-established again at very high magnetic field and observe an unusual vortex dynamics in Bi-2212 superconductors. Destruction of coherence or unusual vortex motion through the grain boundary may be the possible reason for this observed unusual behavior.
Keywords: Bi-based superconductor, Ac susceptibility, Dc magnetization, Vortex dynamics