Regensburg 2010 – scientific programme
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MA: Fachverband Magnetismus
MA 25: Surface Magnetism / Magnetic Imaging I
MA 25.4: Talk
Thursday, March 25, 2010, 11:00–11:15, H23
SP-STM of Co nano-islands on Cu(111) with bulk Cr tips — •Marco Corbetta2, Fabio Donati1,2, Andrea Li Bassi1, Matteo Passoni1, Carlo Casari1, Safia Ouazi2, Yasmine Nahas2, Dirk Sander2, and Jürgen Kirschner2 — 1CNISM, NEMAS and Dipartimento di Energia - Politecnico di Milano, Milano, Italy — 2Max Planck Institut für Mikrostrukturphysik, Halle, Germany
From its first application, SP-STM has been performed using tunneling tips fabricated with a great variety of ferromagnetic (Fe, Ni, Co or Fe-coated W tips) or antiferromagnetic materials (MnNi, MnPt, Cr-coated or Mn-coated W tips). In order to avoid perturbing stray fields induced by strong magnetic polarization of the tip, antiferromagnetic materials are usually preferred [1]. The main drawback of coated tips is that an in-situ preparation is required. Recently an easy, reliable and reproducible procedure for the production of bulk Cr tips has been developed using only a standard electrochemical etching [2]. We produced and used such tips for in-field spin-polarized STM measurements at 7 K on Co nano-islands on Cu(111). The obtained images show a spin resolved high spatial resolution on the Co islands. Changing the magnetic field we measured the variation of the dI/dV signal. We obtained butterfly hysteresis loops which show that the magnetization direction of the tip apex is not pinned but follows the external magnetic field direction, similar to our previous results obtained with Cr-coated W tips [3]. [1] A. Kubetzka et al., Phys. Rev. Lett. 88, 057201 (2002). [2] A. Li Bassi et al., Appl. Phys. Lett. 91, 173120 (2007). [3] G. Rodary et al., Jpn. J. Appl. Phys. 47, 9013 (2008).