Flux trapping on multi-superconducting phase PAT12-C-60-Rb composite: Low-field microwave absorption study

The in-phase and out-of-phase low held microwave absorption (LFMA) signals in a PAT12(C-60)(0.05)Rb-x composite, consisting of superconducting granular Rb3C60 grains embedded in host poly(3-alkyltiophene) (PAT12) matrices, are investigated as functions of temperature and the intensity of trapped field. Temperature dependence of the peak field H-p of the out-of-phase and in-phase LFMA obeys the relation H-p similar to {1-(T/T-c2)}(1/4) and H-p similar to{1-(T/T-cl)(4)}(1/2) respectively, where T-c2 (= 22 K) and T-cl (=26 K) is the critical temperature of respective phase. Threshold field of the flux trapping in the out-of-phase and in-phase LFMA is nearly zero and 150 G respectively. These results support the previous models proposed for the origins of two phases presented in the K-doped CP-C-60 composites. (C) 1997 Elsevier Science Ltd.