Abstract
A Fulde-Ferrell-Larkin-Ovchinnkov (FFLO) state was previously reported in the quasi-2D heavy fermion when a magnetic field was applied parallel to the plane. Here, we conduct NMR studies of this material in a perpendicular field, and provide strong evidence for FFLO in this case as well. Although the topology of the phase transition lines in the phase diagram is identical for both configurations, there are several remarkable differences between them. Compared to , the FFLO phase for is confined in a much narrower region at the low-–high- corner in the plane, and the critical field separating the FFLO and non-FFLO superconducting states almost ceases to have a temperature dependence. Moreover, directing results in a notable change in the quasiparticle excitation spectrum within the planar node associated with the FFLO transition.
- Received 15 May 2006
DOI:https://doi.org/10.1103/PhysRevLett.97.227002
©2006 American Physical Society