Direct measurement of the magnetic penetration depth by magnetic force microscopy

JEEHOON KIM; L. CIVALE; E. NAZARETSKI; N. HABERKORN; F. RONNING; A. S. SEFAT; T. TAJIMA; B. H. MOECKLY; J. D. THOMPSON; R. MOVSHOVIC

SUPERCONDUCTOR SCIENCE AND TECHNOLOGY

IOP PUBLISHING LTD

Lugar: Londres; Año: 2012 vol. 25 p. 112001 - 112007

0953-2048

We present an experimental approach using magnetic force microscopy for measurements of the absolute value of the magnetic penetration depth (lambda) in superconductors. Lambda is obtained in a simple and robust way without introducing any tip modeling procedure via direct comparison of the Meissner response curves for a material of interest to those measured on a reference sample. Using a well characterized Nb film as a reference, we determine the absolute value of lambda in a Ba(Fe0.92Co0.08)2As2 single crystal and a MgB2 thin film through a comparative experiment. Our apparatus features simultaneous loading of multiple samples, and allows straightforward measurement of the absolute value of lambda in superconducting thin film or single crystal samples.