Magnetic force microscopy study of the penetration depth in MgB$_{2}$ thin films

J. KIM; L. CIVALE; EVGUENI NAZARETSKI; N. HABERKORN; JOSH THIBODAUX; ILYA VEKHTER; BRIAN MOECKLY; JOE D. THOMPSON; ROMAN MOVSHOVICH

Dallas

Congreso; APS March Meeting 2011; 2011

American Physical Society

We performed magnetic force microscopy (MFM) investigations of superconducting vortices in thin fillms of MgB2. Our MFM instrument has the capability of scanning multiple samples. Prior to imaging vortices in MgB2, vortex imaging in a Nb thin film was performed to characterize the cantilever's tip. This procedure allows extraction of the penetration depth with only one fitting parameter. Images of two MgB2 films with different thickness were taken as a function of temperature, togetherwith periodic checks of the condition of the magnetic tip via imaging of vortices in the Nb reference sample, during a single cooldown. The temperature dependent penetration depth determined by MFM will be compared to that obtained via SQUID magnetometry on the same samples.