A UHV MOKE magnetometer complementing XMCD-PEEM at the Elettra Synchrotron

Francesca Genuzio,Tomasz Giela,Tevfik Onur Menteş,Jozef Korecki,Piotr Mazalski,Matteo Lucian,Stefano Bonetti,Andrea Locatelli,Giuseppe Cautero,Carlo Alberto Brondin

doi:10.1107/s1600577521002885

Abstract

We report on a custom-built UHV-compatible Magneto-Optical Kerr Effect (MOKE) magnetometer for applications in surface and materials sciences, operating in tandem with the PhotoEmission Electron Microscope (PEEM) endstation at the Nanospectroscopy beamline of the Elettra synchrotron. The magnetometer features a liquid-nitrogen-cooled electromagnet that is fully compatible with UHV operation and produces magnetic fields up to about 140 mT at the sample. Longitudinal and polar MOKE measurement geometries are realized. The magneto-optical detection is based on polarization analysis using a photoelastic modulator. The sample manipulation system is fully compatible with that of the PEEM, making it possible to exchange samples with the beamline endstation, where complementary X-ray imaging and spectroscopy techniques are available. The magnetometer performance is illustrated by experiments on cobalt ultra-thin films, demonstrating close to monolayer sensitivity. The advantages of combining in situ growth, X-ray Magnetic Circular Dichroism imaging (XMCD-PEEM) and MOKE magnetometry into a versatile multitechnique facility are highlighted.

Highlights

The downscaling of magnetic structures, driven by the need for ever smaller and efficient magnetic storage, has stimulated intense research in systems with film thicknesses limited to a few atomic layers and a lateral size well below the micron level (Vaz et al, 2008)
The presence of high voltages in the sample environment, the sensitivity of electron beams to applied magnetic fields, the probing depth limited to a few nanometres and the extra effort needed to obtain a full vectorial magnetization map all constitute challenges in using XPEEM as a stand-alone complete magnetic characterization technique
We describe here a Magneto-Optical Kerr Effect (MOKE) magnetometer that has been developed to work in tandem with the Spectroscopic PhotoEmission and Low-Energy Electron Microscope (SPELEEM III, Elmitec GmbH) installed at the Nanospectroscopy beamline at the Elettra synchrotron (Locatelli et al, 2006; Menteset al., 2014)

Summary

A UHV MOKE magnetometer complementing XMCD-PEEM at the Elettra Synchrotron

Francesca Genuzio,a Tomasz Giela,a,b Matteo Lucian,c Tevfik Onur Mentes,c* Carlo Alberto Brondin,d Giuseppe Cautero,c Piotr Mazalski,e,f Stefano Bonetti,d,g Jozef Koreckif and Andrea Locatellic*. We report on a custom-built UHV-compatible Magneto-Optical Kerr Effect (MOKE) magnetometer for applications in surface and materials sciences, operating in tandem with the PhotoEmission Electron Microscope (PEEM) endstation at the Nanospectroscopy beamline of the Elettra synchrotron. The magnetometer features a liquid-nitrogen-cooled electromagnet that is fully compatible with UHV operation and produces magnetic fields up to about 140 mT at the sample. Longitudinal and polar MOKE measurement geometries are realized. The magneto-optical detection is based on polarization analysis using a photoelastic modulator. The sample manipulation system is fully compatible with that of the PEEM, making it possible to exchange samples with the beamline endstation, where complementary X-ray imaging and spectroscopy techniques are available. The advantages of combining in situ growth, X-ray Magnetic Circular Dichroism imaging (XMCD-PEEM) and MOKE magnetometry into a versatile multitechnique facility are highlighted

Introduction

System description

Vacuum chamber layout

Data acquisition and processing

Application examples

Conclusions