Properties and Types of Superconductors

Abstract

The disappearing of electrical resistance below the critical temperature (Tc) is known as superconductivity discovered by Kamerlingh Onnes in 1911. Superconductors are consisted of two categories namely type I and type II also called soft and hard superconductors, respectively. Type I superconductors obey the Meissner effect while type II superconductors do not. The superconducting compounds are divided into three categories, (i) Metal based systems, (ii) Copper oxides (cuprates) and (iii) Iron based superconductors (IBSC). Metal-based superconductors are combination of cubic crystal configuration named the A15 structure. Initial IBSC was revealed in 2006 for LaFePO; nevertheless, Tc stayed as small as ~4 K. High-Tc compounds were then expressed for LaFeAsO1–xFx by means of Tc = 26 K in 2008. Superconductors have considerable positions in the lower temperature magnet applications such as MRI, nuclear magnetic resonance and superconducting quantum interference.