Physics Department Faculty

Dr. Vladimir Kozhevnikov, Assistant Professor
MC 526, 918-595-7193,

National Science Foundation

The magical world of superconductors with Dr. Vladimir Kozhevnikov

Magnetic Field Profile in a Classical Superconductor

Vladimir Kozhevnikov, Tulsa Community College,DMR 0904157

Superconductivity (SC) is a striking phenomenon of immense importance for applications. Discovered 100 years ago it unchangeably leads the “hotlist” of condensed matter physics; 10 Nobel Prizes have been awarded in this fields.  The hallmark of SC is exclusion of magnetic field: it can penetrate into SC phase for only a small depth. The depth magnitude and the field profile over it are determined by microscopic parameters of SCs. In this project we measure magnetic filed profile in classical SCs with the aim to determine the “most wanted” parameters: the London penetration depth and the Pippardcoherent length. This year we measured, for the first time, the field distribution in indium. Measurements were performed with Low-Energy muonSpin Rotation technique in Paul ScherrerInstitute in Switzerland. The theory predicts that the filed profile in this metal is strongly nonexponential.  As seen from the figure, this is exactly what we have found.  Quantitative discrepancies between experimental data and theory (red line) will be clarified in upcoming experiments with muonsand polarized neutrons.

Muonspectra for superconducting and normal (black) states of indium.

Magnetic field in indium in the Meissnerstate vs energy of implanted muons.  Red lineis prediction of the Pippardand BCS theories and blue lineis prediction  of the London theory.

Tulsa Community College is a two-years institution of primary high education. To attract students to physics PI organized a class “Selected Topics in Physics”. The class meets once a week; each meeting students make presentations on a topic associate with the project, such as He4 and He3 properties, discovery and current status of superconductivity, qualitative basics of superconductivity theory, magnetometry  and SQUID magnetometer, basics of special relativity and particle physics, standard model, muonspectroscopy and neutron optics. In spring semester of this year the class was offered for the first time. Three students were enrolled, each student made four presentations. Students attended March APS Meeting in Portland and participated in muonmeasurements in the Paul ScherrerInstitute. Students really love this class! In fall semester the class enrollment is five students.  

Dr. A. Suter(PSI) and TCC student Jeffrey Healy disassemble cryostat after experiment at Low-Energy Muonfacility in Paul Scherrer Institute.

p50-52_Vladimir_Kozhevnikov_HR.pdf2.09 MB