Quaternary Borocarbides- Discovery and Overview

Abstract

After the revolutionary discovery of superconductivity in high Tc oxide materials (HTSC) by Bednorz and Muller in 1986 [1], discovery of superconductivity in intermetallic quaternary borocarbide [2, 3, 4, 5, 6] is a landmark in the field of superconductivity. The discovery revived research in superconductivity in intermetallics for a variety of reasons and led to the new subject of superconductivity and magnetism in quaternary borocarbides, which is the theme of this NATO Advanced Research Workshop (ARW). The field of quaternary borocarbides (QBC) originated with the discovery of superconductivity at an elevated temperature, Tc ~12–15 K in Y-Ni-B-C system at TIFR, Bombay [2, 3, 4, 5, 6] followed by the finding of superconductivity in Y-Pd-B-C system (Tc ~23 K) [7] and in RNi2B2C (R = Y, Lu, Tm, Er, Ho) (Tc ~15.5 K, 16.5 K, 11 K, 10.5 K, 8K, respectively) [8,9]. In this article, our experiments that led to the discovery of superconductivity in Y-Ni-B-C are described followed by an overview of subsequent developments, including highlights of some of our work in the field, indicating the unique aspects of superconductivity, magnetism and their interplay in QBC. With this workshop having extensive representation from various research groups, the other articles will give details of the various aspects of the properties of QBC. The reader is also referred to several other review articles in the literature [10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20].