화학공학소재연구정보센터
Journal of Vacuum Science & Technology B, Vol.14, No.4, 3126-3130, 1996
Imaging of Ferromagnetic Domains Using Photoelectrons - Photoelectron Emission Microscopy of Neodymium-Iron-Boron (Nd2Fe14B)
Ferromagnetic domains of a single crystal of neodymium-iron-boron, Nd2Fe14B (one of the strongest permanent magnetic materials known) are imaged by focusing a beam of photoelectrons with electrostatic optics in a photoelectron emission microscope. Photoelectrons emitted from the surface are deflected laterally into two opposite directions by stray magnetic fields that exist above the domains. The photoelectron beam is partially split into two. Magnetic contrast is produced by blocking part of the beam and imaging with an edge of the beam. The magnetic contrast mechanism appears to be similar to the type I magnetic contrast mechanism known from scanning electron microscopy, in which stray magnetic fields above the ferromagnetic domains deflect secondary electrons either towards or away from the electron detector. Upon heating the sample above the Curie temperature, the ferromagnetic domains gradually disappear, as expected for a second order phase transition. They reappear upon cooling.