Search for new superconducting materials
The search for materials with novel properties, new superconductors in particular, is a difficult and sometimes tedious task. It is difficult because a deliberate search for new superconducting materials in a particular system is rarely successful. As a consequence, the discovery of these new materials has been mostly accidental since the discovery of the phenomenon. Moreover this is a tedious task because the systems under study are usually materials consisting of several elements with complex phase diagrams. The interesting novel superconducting properties generally occur in a very narrow phase diagram region where superconducting and non-superconducting phases are likely to coexist. In some ways, the search for new materials is akin to the search for a "needle in a haystack" in which most of the material is "irrelevant".
Based on the past history of discoveries in superconductivity clearly some novel unconventional ideas are needed. Our method consists of a fast process for discarding most of the ("uninteresting") non-superconducting part of a multinary phase diagram. This is done by combining a parallel method for the preparation of highly inhomogeneous samples ("phase spread alloy") together with a fast, sensitive screening using Magnetic Field Modulated Microwave Spectroscopy (MFMMS). Once a sample containing a minority superconducting phase is identified, comprehensive and quantitative structural, transport and magnetic methods are applied to identify the phase responsible for the superconductivity.