Non Resonant Microwave Absorption (NRMA) Anomalies in High Temperature Superconductors (HTS) Relevance of Electromagnetic Interactions (EMI) and Energy Stabilized Josephson (ESJ) Fluxons

Abstract

High temperature superconductors (HTS) due to their higher operating temperatures, 2dimensional (2D) layered structure and very short coherence length (ξ) are known to show some interesting properties especially magnetic field dependent microwave (MW) absorption effects at very low magnetic fields of the order of zero gauss; Kadam et al.1987; Blazy et al.1987, 1988, 1989;) while carrying out energy /absorption studies at MW frequencies. One striking example of this is the appearance of very strong non-resonant microwave absorption (NRMA) signal centered around zero magnetic field in the superconducting state at near below Tc in cuprate based HTS :YBCO, reported by Bhat et al.(1987) using conventional electron spin resonance (ESR) spectrometer. This was followed by reports on other cuprate based HTS (Portis et al.,1987, Dulcic et al.1987,1988,1989,1990; Pakulis & G.V.Chandershekar,1989; Sugawara et al., 2000;Hashmizume et al.2001; Padam et al.,1999) and also on a different variety of superconductors like: borocarbides (Kadam et al.,1994), oxyflorides (Kadam et al.,1995) alkali fullerides (Roberts,1998-II), granular conventional low-Tc typeI [Pb, Al, Sn, In etc.]/type II [Nb, Nb3Sn, Nb3Ge/PbMoS6O8 etc.] (Kheifetsand et al., 1990; Blazey et al.1988,1989; Suss et al,1989;Kataev et al.,1991;Baranowsky et al.1991;Moorjani et al.1990; Bele et al.1994; Blazey et al 1987;Veinger et al. 1995),MgB2(S.Sarangi & S.V.Bhat, Joshi et al.,2002) including newly discovered iron pniticide (Panarina et al. 2010; Pascher et al.2010 etc. ).Before coming to the actual problem, what follows is a brief introduction of the NRMA studies done before the advent of HTS.