Nanoscale magnetic field mapping with a single spin scanning probe   magnetometer
  We demonstrate quantitative magnetic field mapping with nanoscale resolution, by applying a lock-in technique on the electron spin resonance frequency of a single nitrogen-vacancy defect placed at the apex of an atomic force microscope tip. In addition, we report an all-optical magnetic imaging technique which is sensitive to large off-axis magnetic fields, thus extending the operation range of diamond-based magnetometry. Both techniques are illustrated by using a magnetic hard disk as a test sample. Owing to the non-perturbing and quantitative nature of the magnetic probe, this work should open up numerous perspectives in nanomagnetism and spintronics. 
L. Rondin, J.-P. Tetienne, P. Spinicelli, C. Dal Savio, K. Karrai, G.   Dantelle, A. Thiaville, S. Rohart, J.-F. Roch and V....
cond-mat.mes-hall