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CMP-Seminar

Title: Anisotropy of Superconducting State Properties in Various High-Tc Superconductors

Speaker:  Prof. Roman Puzniak Institute of Physics, Polish Academy of Sciences, Poland

Location:  Room 616, Physics Building

Time: 14:00-15:00, Tue, June 10 2014

Abstract:
A temperature dependent anisotropy was observed in some superconductors, especially in MgB2, and was explained as a consequence of the presence of two superconducting gaps. Similar temperature dependence was also observed in iron-based superconductors. Later on, the study of the cuprate superconductor SmBa2Cu3O7-δ has shown that the temperature dependence of the anisotropy is observed also for this class of superconductors. Temperature variation of the anisotropy strongly depends on the doping level. The weak temperature dependence of the out-of-plane anisotropy parameter for overdoped YBa2Cu3O7 single crystal was found too. This raises the question whether the temperature dependence of the anisotropy is a common property of all layered high-Tc superconductors and how it is linked to the gap structure. Importantly, besides superconductivity, various iron-based compounds exhibit coexisting magnetic order. This order can be influenced by an external magnetic field, making iron-based superconductors a template for magnetic-field tuned applications.

Biography:
Roman Puzniak is specialized in solid state physics, superconductivity, magnetism, and phase transition phenomena. He received a Ph.D. degree in 1987 and Dr. Hab. degree in 2004. He served at the Institute of Physics of the Polish Academy of Sciences as an Associate Professor (2005-2010); Head of the Group of Phase Transitions (since 2008); Extraordinary Professor (2010-2013), Ordinary Professor (since 2013), Deputy Director for Scientific Matters (since 2014). His activities included superconductivity of multigap superconductors, superconducting state properties of homologeneous series of high-Tc superconductors, pinning and critical currents in superconductors, and influence of pressure on superconductivity and on magnetic properties of manganites. He is coauthor of three papers cited more than 150 times. He is member of American Physical Society (since 1994) and Polish Physical Society (since 1999).