Critical field anisotropy in (TMTSF)2 CLO4 in the basal plane
Abstract
We have performed detailed measurements of the critical field of (TMTSF)2 ClO4 in the plane perpendicular to the highly conducting a axis. We find a large anisotropy with the field in the c direction having a value which is more than an order of magnitude less than along the b direction. The b axis critical field is only slightly (50%) less than the a axis (the highly conducting direction). The angular and temperature dependences suggest that the anisotropy is a band structure effect along b and c, but that the a direction critical field is Pauli limited. These results imply that critical field anisotropy in the directions parallel and perpendicular to the highly conducting a axis cannot be used go obtain information about the band structure anisotropy and that the observed superconductivity is singlet rather than triplet. © 1982.