Atomic force microscopy of magnetic samples using optical detection methods

Abstract

An atomic force microscope is an instrument that is capable of imaging magnetic, electric and van der Waals forces with a very high resolution. In this thesis, different methods for detecting the displacement of the force sensing lever in such an atomic force microscope are discussed. Special emphasis is given to optical detection methods that are used in conjunction with a vibrating lever. The three optical systems that are discussed are based on (1) the heterodyne interferometer, (2) the homodyne interferometer, and (3) a new design that utilizes feedback into a laser diode. Images of a hard disk drive head and of domains in a TbFeCo thin film sample that were obtained with the heterodyne system are presented. Also presented are images of domains in a different TbFeCo sample and of interdigital fingers that were collected with the novel laser diode system.