Scanning Electron Microscopy with Polarization Analysis (SEMPA) and its Applications
This chapter reviews Scanning Electron Microscopy with Polarization Analysis (SEMPA), a technique for directly imaging the magnetic microstructure of surfaces and thin films. SEMPA relies on the fact that secondary electrons emitted from a magnetic sample in a Scanning Electron Microscope (SEM) have a spin polarization which reflects the net spin density in the material. This spin density, in turn, is directly related to the magnetization of the material. By measuring the secondary electron spin polarization, SEMPA can be used for direct, high resolution imaging of the direction and relative magnitude of a sample's magnetization, in the same manner as a SEM uses the measured secondary electron intensity for imaging topography. The purpose of this review is to present a brief overview of the technique and to describe the types of magnetic imaging applications for which SEMPA is best suited.
Experimental Methods in the Physical Sciences, Volume 36: Magnetic Imaging and its Applications to Materials