R. Modler et al., FIRST-ORDER TRANSITION BETWEEN WEAK AND STRONG PINNING IN CLEAN SUPERCONDUCTORS WITH ENHANCED SPIN SUSCEPTIBILITY, Physical review letters, 76(8), 1996, pp. 1292-1295
Dilatometric and magnetic experiments on high-quality single crystals
of the superconducting compounds UPd2Al3 and CeRu2, which have enhance
d spin susceptibilities, demonstrate a first-order transition between
weak and strong pinning at T < 0.9T(c) (H > 10 kOe). This is compatibl
e with a staggered order parameter due to the formation of a ''Fulde-F
errell-Larkin-Ovchinnikov'' state.