Investigation of charge and superconducting correlations in cuprates using nonlinear conductivity

Došlić, Marija (2014) Investigation of charge and superconducting correlations in cuprates using nonlinear conductivity. Diploma thesis, Faculty of Science > Department of Physics.

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Abstract

An apparatus for measuring nonlinear conductivity in the radio-frequency range at high powers has been devised. Nonlinear conductivity was measured on three samples (YBa2Cu3O6.6 (YBCO), La2−0.125Sr0.125CuO4 (LSCO), La2−xEu0.2SrxCu O4 (LESCO)) above the superconducting transition, in the range where striped order occurs. Nonlinear response of an undoped ironarsenide sample, known to undergo an electronic nematic phase transition at Tnem=138 K was also measured. Comparing the measured results and qualitative predictions obtained from a classical model, we were able to determine the dependence of the stripe order parameter on temperature in YBCO and LESCO. Measurements on LESCO have also revealed the presence of an intermediate state, marked by a sharp peak, similar to the one measured in the iron arsenide at Tnem. It probably corresponds to stripe melting, i.e. an orientational symmetry breaking state independent of structure. Nonlinear conductivity measurements on LSCO revealed no stripe order phase.

Item Type: Thesis (Diploma thesis)
Supervisor: Požek, Miroslav
Date: 15 September 2014
Number of Pages: 48
Subjects: NATURAL SCIENCES > Physics
Divisions: Faculty of Science > Department of Physics
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 14 Oct 2014 09:24
Last Modified: 22 Aug 2017 08:21
URI: http://digre.pmf.unizg.hr/id/eprint/3031

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