The development of a low temperature MFM

Abstract

In order to image the magnetic contrast of a magnetic semiconductor structure with a Curie temperature well below room temperature a low temperature Magnetic Force Microscope (MFM) is developed. As a first step Atomic Force Microscope (AFM) measurements and calibrations have been performed at room temperature, liquid nitrogen temperature (77K) and liquid helium temperature (4K). The piezo scanners show a large nonlinearity that differs for the three temperatures. The images need to be corrected for these non-linearities in order to get the correct image sizes. In AFM mode 4nm high features can be distinguished in clustered groups of quantum dots at low temperature. The higher Q-factor of the cantilever at lower temperature has a strong effect on the imaging modes that we have studied. This project ended successfully as we have were able to perform high resolution MFM imaging at 4K.

Date of Award	31 Jul 2009
Original language	English
Supervisor	N.A.J.M. Kleemans (Supervisor 1) & Paul M. Koenraad (Supervisor 2)