Record Details

Interplay between magnetism and superconductivity in high Tc Superconductors

Shodhganga@INFLIBNET

View Archive Info
 
 
Field Value
 
Title Interplay between magnetism and superconductivity in high Tc Superconductors
—
 
Contributor Khandka, Sarita
 
Subject Physics
Tc Superconductors
 
Description The effect of antiferromagnetic order on superconducting order parameter ( D) in
newlinemultilayer cuprate superconductors has been studied by using double time retarded
newlineGreen s function technique, and expression for D has been obtained. The
newlineexpression is found to be depending on the antiferromagnetic order parameter ( f)
newlinealong with temperature (T). It has been found that at low temperatures
newlinesuperconducting order parameter decreases linearly with increasing
newlineantiferromagnetic order parameter. But at the temperature close to transition temperature (TC), this linearity violated and uperconducting order first decreases
newlinesuddenly and then there is gradual decrease with increasing antiferromagnetic order. This shows that at near to transition temperature the area of co-existence of antiferromagnetism and superconductivity decreases. Results also show that for
newlinecuprates having TC below 35 k, antiferromagnetic order co-exist with
newlinesuperconductivity and could be helpful for superconductivity. The magnetic properties of LnOFeAs system has also been studied using
newlineanisotropic Heisenberg model with three in-plane (J1, J2, J3) and one out-of-plane
newline(J ^) exchange interactions. Starting with stripe configuration with two
newlineinterpenetrating sublattices such that the spins are always oppositely aligned in
newlinetwo sublattices, the expression for sublattice magnetization and Néel Temperature
newline(TN) has been obtained using Green s function technique within random phase
newlineapproximation (RPA). Using the expression for Néel temperature, variation of TN with J ^ has been studied. The effect of J ^ on the sublattice magnetization has been
newlinealso studied. For realistic values of exchange coupling constants, Néel
newlineTemperature of LnFeAsO system (Ln = La, Pr and Ce) has been evaluated. The theoretical results are compared with experimental results and found in good agreement.
Summary p. 85-87, References p. 88-95
 
Date 2013-01-23T07:22:10Z
2013-01-23T07:22:10Z
2013-01-23
n.d.
2012
2012
 
Type Ph.D.
 
Identifier http://hdl.handle.net/10603/6620
 
Language English US
 
Relation --
 
Rights university
 
Format 95p.
--
None
 
Coverage Physics
 
Publisher Allahabad
Sam Higginbottom Institute of Agriculture, Technology and Sciences
Department of Physics
 
Source INFLIBNET