A new custom-made sample holder for high temperature and in stu application of magnetic fields in a photoemission electron microscope

Abstract

We present a new custom-made sample holder system for its use in Elmitec Low Energy and PhotoEmission Electron Microscopes. It comprises two different sample holder bodies: one with a filament for electron bombardment heating up to more than 1500 K and another one with integrated electromagnets for the in situ application of small magnetic fields either in- plane or out-of-plane. The sample itself is placed on a platelet with a central top hat shape which is transferred between both holder types. Thus it is possible to prepare or grow samples at elevated temperatures and then investigate their behavior under magnetic fields without ever leaving the ultra-high vacuum system. This design opens up new possibilities for the study of magnetic properties of surfaces, thin films and nanostructures which cannot be exposed to air. As an example of the performance of the setup we present the growth of magnetite on Ru(0001) by high temperature oxygen-assisted molecular beam epitaxy. The nucleation and growth process are observed in real time by means of Low Energy Electron Microscopy (LEEM), which enables to optimize the growth parameters. Imaging of the magnetic domain distribution of the resulting magnetite microstructures is done via XMCD-PEEM (X-ray Magnetic Circular Dichroism Photoemission Electron Microscopy). Finally, the switching characteristics of individual magnetite microstructures under applied field was investigated. Our results illustrate the feasibility to change the magnetic state of the in-situ grown materials at tens of nm scale resolution.