Evidence for a Nodal Energy Gap in the Iron-Pnictide Superconductor LaFePO from Penetration Depth Measurements by Scanning SQUID Susceptometry

Journal Article · Wed Feb 24 00:00:00 EST 2010 · Phys.Rev.Lett.103:127003,2009

OSTI ID:972670

Hicks, Clifford W.; Lippman, Thomas M.; Huber, Martin E.; Analytis, James G.; Chu, Jiun-Haw; Erickson, Ann S.; Fisher, Ian R.; Moler, Kathryn A.

We measure changes in the penetration depth {lambda} of the T{sub c} {approx} 6 K superconductor LaFePO. In the process, scanning SQUID susceptometry is demonstrated as a technique for accurately measuring local temperature-dependent changes in {lambda}, ideal for studying early or difficult-to-grow materials. {lambda} is found to vary linearly with temperatures from 0.36 to {approx} 2 K, with a slope of 143 {+-} 15 {angstrom}/K, suggesting line nodes in the superconducting order parameter. The linear dependence up to {approx} T{sub c}/3, similar to the cuprate superconductors, indicates well-developed nodes.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 972670
• Report Number(s): SLAC-REPRINT-2010-021; PRLTAO; TRN: US201005%%243
• Journal Information: Phys.Rev.Lett.103:127003,2009, Journal Name: Phys.Rev.Lett.103:127003,2009; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CUPRATES
ENERGY GAP
ORDER PARAMETERS
PENETRATION DEPTH
SUPERCONDUCTORS
MATSCI