Jeffrey Vit, Department of Physics, The University of Texas at Austin

"Low-Temperature Magnetic Force Microscopy with a Simple Design: Analyzing the Magnetic Domains of a Simple Hard Disk Drive"

Abstract: The first part of this dissertation introduces the theoretical background for the Magnetic Force Microscope (MFM) and the theoretical basis for magnetic domains. The second part will address issues we have come across on previous designs and how our newer design overcomes these issues. Along with the construction of our low temperature magnetic force microscope (LT-MFM) and its operation. The third part focuses on the LT-MFM experimental investigation on a simple memory storage disk.

Scanning probe microscopy (SPM) was first developed to study various electronic properties of different materials, such as imaging high Tc superconductors. Soon after, the SPM grew and expanded in terms of techniques and properties that could be imaged. For example, some variations of the SPM family have developed into powerful techniques to characterize magnetic features or even studying nonlinear effects in living samples. These being the MFM and Second-Harmonic imaging microscopy (SHIM). The former, and for the focus of this dissertation, was widely used for imaging surface magnetic properties from hundreds of micrometers down to the nanometer scale. With our new LT-MFM, we studied two hard disk drives (HDD) and have concluded that their magnetic domain structure closely matches with other former studies on similar HDD samples. In addition, with its simple design and open architecture, our homebuilt LT-MFM has proved, once again, that a low cost and efficient microscope can be built with minimal loss to its magnetic domain resolution.