A. Yamashita et al., ANOMALOUS FIELD-DEPENDENCE OF MAGNETIC PENETRATION DEPTH IN THE VORTEX STATE OF CERU2 PROBED BY MUON SPIN ROTATION, Physical review letters, 79(19), 1997, pp. 3771-3774
Magnetic penetration depths in the mixed state of a heavy-fermion supe
rconductor CeRu2 have been measured by muon spin rotation. An anomalou
s increase of the observed penetration depth associated with the hyste
resis peak of magnetization strongly suggests a new vortex phase, poss
ibly a generalized Fulde-Ferrel-Larkin-Ovchinnikov state, near the upp
er critical field. [S0031-9007(97)04432-3].