Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 9: Magnetic Particles, Clusters
MA 9.16: Talk
Monday, March 22, 2010, 19:15–19:30, H23
The role of the tip material for switching fields measured by spin polarized STM — •yasmine nahas1, safia ouazi1, marco corbetta1, fabio donati1,2, hirofumi oka1, sebastian wedekind1, guillemin rodary1, dirk sander1, and jürgen kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany — 2CNISM, NEMAS and Dipartimento di Energia - Politecnico di Milano, Milano, Italy
Spin polarized scanning tunneling microscopy (SP STM) enables us to probe the magnetism of single objects down to the single atom level. Switching fields of individual Co islands on Cu(111) were already measured using Cr coated W tips [1]. We study the same system using bulk Cr tips fabricated by standard electrochemical etching [2]. The switching fields of Co islands measured with a bulk Cr tip are consistently larger as compared to those obtained with Cr coated W tips. Whereas we measured with the Cr coated W tip a typical switching field of 0.6 T for a Co island with 1800 atoms at 8 K, we measure 1.2 T for an island of the same size using the bulk Cr tip. This surprising result is discussed in view of the role of the island size, temperatures, the island environment and tip material for the magnetic switching field.
[1] G. Rodary et al., Jpn. J. Appl. Phys. 47, 9013 (2008).
[2] A. Li Bassi et al., Appl. Phys. Lett. 91, 173120 (2007).