The Study Of Upper Critical Field Calculetion Of Superconducting Magnesium Diboraide

Magnesium diboride(MgB2) has joined the class of high Tc superconductors following therndiscovery of superconductivity in this compound in 2001 below Tc 40k. A large part ofrnthe excitement is due to the vast amount of unusual properties originating from the involvementrnin superconductivity of two sets of bands that are of a very different nature. Because ofrnthe different dimensionality of the two sets of bands,this”two band superconductivity” leadsrnto a complex behavior of the anisotropic superconducting state properties as a function ofrnmagnetic field and temperature. The purpose of this thesis is to study the upper critical fieldrn(Hc2) of two-band s-wave superconducting magnesium diboride(MgB2) in the vicinity of Tcrnusing a two-band Ginzburg-Landau(GL) theory. The analytical formula of Hc2(T) involvingrnanisotropy of order parameter and anisotropy of effective-mass are found. The parametersrnof the upper critical field in ab-plane(Habrnc2 ) and c-axis (Hcrnc2) can be found by fitting to the experimentalrndata. In addition to this we have considered the linearized two band Eilenbergerrnequations to calculate the upper critical field of superconducting magnesium diboride. Finallyrnby taking the ratio of the upper critical field ( the fields in ab-plane and c-axis) we triedrnto show the anisotropy property of superconducting magnesium diboride. We observe thatrnthe ratio of the two fields strongly depends on temperature. So, this ratio of upper criticalrnfield is in the range of experimental result and temperature dependent.rnKey words: S-wave superconductor,anisotropy two-band superconductors,Ginzburg-Landaurnapproach,Eilenberger equations,Magnesium diboride

Get Full Work

Report copyright infringement or plagiarism