M.Sc Thesis
M.Sc Student Lubashevsky Yuval The Origin of the Pseudogap Department of Physics Professor Amit Keren

Abstract

In this work we deduced the HTSC's Pseudogap critical temperature, known as T*. We did that by measuring the magnetic susceptibility on high temperatures region. We measured the CLBLCO system, in which small changes in the superconductivity properties can be made by making small changes in the chemical components. Changes of T* can be detected as a function of the changes in the chemical components and, of-course, as the function of the doping levels.

Previous work in our group demonstrated that in the cuprates superconductors: Tc proportional Jfns where Tc is the superconductor transition temperature, Jf a magnetic energy scale for a given cuprates family,  and ns is the superconducting carrier density. We have also found correlation, using a scaling relation, between Tcmax (SC Temperature at optimal doping), TN (the Neel temperature) and Tg (the spin-glass temperature) for a given family.

In this work, we enhance this previous results by including T* in the scaling relation. In addition, we found new properties of T* by comparing it to the other critical temperature. The most important conclusion is that T* is affected by 3D magnetic interaction and not 2D like Tc