CENT affiliated student Mr. Fatai Olawale Bakare of Physics Department successfully presented his MS Thesis on 21st of April, 2016. His thesis details are given below:
Title: Characterization of Dissipative States in niobium titanium nitride Superconducting Filaments
Superconducting materials have potential application in radiation detection because of their special properties such as sensitive to incident radiation at optical wavelengths. Superconducting single-photon detectors (SSPDs) are those single-photon detectors that are sensitive to single-photon at visible and infrared wavelengths regime. These devices are highly promising for photon-registering technology for optical wavelength due to their high efficiency, high timing resolution, excellent recovery time as well as low dark count rate. These devices employ the concept of dissipative states in narrow superconducting materials. In this work, overcritical current pulses (I > Ic) have been used to create dissipative states, Phase-slip centers (PSC), in NbTiN superconducting filaments at different temperature below the critical temperature Tc. The voltage responses which initiated the generation of the PSC were observed after certain delay time td. By employing a modified Time-Dependent Ginzburg-Landau (TDGL) theory, one is able to analyze this time and subsequently deduced the time taken for the generated heat to escape the substrate τd. The τd was found to be independent of the temperature for all samples.