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AM: Magnetismus

AM 18: Postersitzung Fürstenberghaus

AM 18.39: Poster

Mittwoch, 19. März 1997, 14:30–17:30, F"u

Factor 2 improvement of the resolution in magnetic imaging with an Magneto Optical STM — •R. Schad¹, M. Stoelinga¹, M.W.J. Prins², R.H.M. Groeneveld¹, H. van Kempen¹, and H.W. van Kesteren² — ¹EVSF2, Katholieke Universiteit Nijmegen, Toernooiveld 1, NL 6515 ED Nijmegen — ²Philips Research Lab, Eindhoven

For magnetic imaging with sub-micron resolution of topography and magnetic domain structure we developed a Magneto-Optical Near-Field STM. In this set up a semiconducting tip is used as a local photo detector in the optical near field regime. Illumination of the multilayers with circularly polarised light gives rise to contrast due to Circular Dichroism, producing a tunnel current depending on the local magnetisation of the sample. The resolution is determined by the active volume of the tip which produces carriers for the tunnel process. This volume is defined by the penetration depth of the light and the electronic properties of the GaAs. In this study we varied the wavelength of the laser light from 633 nm to 532 nm. In this way we improved the resolution of magnetic imaging by a factor of 2 being now 100 nm. This microscope works under ambient conditions and in magnetic fields.