Abstract
The effects of anisotropic gap structures on a diamagnetic response are investigated in order to demonstrate that the field-angle-resolved magnetization [] measurement can be used as a spectroscopic method to detect gap structures. Our microscopic calculation based on the quasiclassical Eilenberger formalism reveals that in a superconductor with a fourfold gap displays a fourfold oscillation reflecting the gap and Fermi-surface anisotropies, and the sign of this oscillation changes at a field between and . As a prototype of unconventional superconductors, magnetization data for borocarbides are also discussed.
- Received 15 October 2004
DOI:https://doi.org/10.1103/PhysRevLett.94.067007
©2005 American Physical Society