Contents. 1 Imaging Magnetic Microspectroscopy W. Kuch 1

Transcription

1 1 Imaging Magnetic Microspectroscopy W. Kuch Microspectroscopy and Spectromicroscopy - An Overview Scanning Techniques Imaging Techniques Basics X-Ray Magnetic Circular Dichroism Photoelectron Emission Microscopy About Doing XMCD-PEEM Microspectroscopy Experiment H Data Analysis Specific Examples Ultrathin fcc Fe Films Spin Reorientation Transition in Co/Ni Bilayers Summary and Outlook 23 References 24 2 Study of Ferromagnet-Antiferromagnet Interfaces Using X-Ray PEEM A. Scholl, H. Ohldag, F. Nolting, S. Anders, and J. Stöhr Introduction Photoemission Electron Microscopy X-Ray Absorption Spectroscopy X-Ray Magnetic Linear Dichroism (XMLD) X-Ray Magnetic Circular Dichroism (XMCD) Temperature Dependence of X-Ray Magnetic Dichroism Experiment Antiferromagnetic Structure of LaFe0 3 Thin Films Exchange Coupling at the Co/NiO(001) Interface Angular Dependence of Domain Contrast in NiO(OOl) Polarization Dependence of Domain Contrast 43

2 VIII Contents Coupling Between Co and NiO-AFM Reorientation Interfacial Spin Polarization in Co/NiO(001) Summary 47 References 48 3 Time Domain Optical Imaging of Ferromagnetodynamics B.C. Choi and M.R. Freeman Introduction Historical Background of Time-Resolved Techniques Instrumentation Physical Principle of Magneto-Optic Effect Time-Resolved Experiments Experimental Apparatus Representative Results in Thin Film Microstructures Picosecond Time-Resolved Magnetization Reversal Dynamics Precessional Magnetization Reversal and Domain Wall Oscillation Conclusion and Outlook 64 References 65 4 Lorentz Microscopy A.K. Petford-Long and J.N. Chapman Introduction Experimental Requirements Basic Instrumental Requirements Specimen Requirements Basic Theory Imaging Modes in Lorentz Microscopy Fresnel Mode Foucault Mode Low-Angle Electron Diffraction Differential Phase Contrast (DPC) Imaging Electron Holography In-situ Magnetizing Experiments - Use of the TEM as a Laboratory Application to Spin-Valves and Spin Tunnel Junctions Summary and Conclusions 85 References 85 5 Electron Holography of Magnetic Nanostructures M.R. McCartney, R.E. Dunin-Borkowski, and D.J. Smith Introduction Basis of Electron Holography Theoretical Background 89

3 IX Experimental Setup Practical Considerations Applications Applications to Magnetic Materials FePt Thin Films NdFeB Hard Magnets Magnetic Nanostructures Co Spheres Magnetotactic Bacteria Pattemed Nanostructures Outlook 106 References SPLEEM E. Bauer Hl 6.1 Introduction Hl 6.2 Physical Basis of Beam-Specimen Interactions Experimental Setup and Procedure Applications Single Layers Nonmagnetic Overlayers Sandwiches Other Topics Summary 133 References SEMPA Studies of Thin Films, Structures, and Exchange Coupled Layers H.P. Oepen and H. Hopster Introduction Instrumentation Basics: Secondary Electron Emission Spin-Polarization Analyzer Electron Column Polarization Vector Analysis Case Studies Ultrathin Films Films with Perpendicular Magnetization Films with In-Plane Magnetization Exchange Coupled Films Decoration Technique Imaging in Magnetic Fields Conclusions 164 References 164

4 X Contents 8 Spin-SEMofStorage Media K. Koike ^ fig 8.1 Introduction j^o 8.2 HDD Recording Media Obliquely Evaporated Recording Media Magneto-Optical Recording Media Concluding Remarks 17g References, 7 o 9 High Resolution Magnetic Imaging by Local T\inneling Magnetoresistance W. Wulfhekel 18] 9.1 Introduction 18j 9.2 Experimental Setup Magnetic Switching and Magnetostriction of the Tip Magnetic Imaging of Ferromagnets Magnetic Susceptibility The Contrast Mechanism Conclusions and Outlook 200 References ^m 10 Spin-Polarized Scanning lunneling Spectroscopy M. Bode and R. Wiesendanger Introduction Experimental Setup Experiments on Gd(0001) Domain and Domain-Wall Studies on Ferromagnets Surface Spin-Structure Studies of Antiferromagnets 215 Conclusions 299 References Magnetic Force Microscopy: Images of Nanostructures and Contrast Modeling A. Thiaville, J. Miltat, and J.M. Garcia Introduction: The Magnetic Force Microscope Principle of MFM MFM Layout [][[][[[ Modes of Operation Gallery of Nanostructures MFM Images Ultrathin Films '.'.'.'.'.'.'.' Nanoparticles Nanowires Patterned Elements MFM Contrast in Absence of Perturbations 234

5 XI Two-Dimensional Case One-Dimensional Case MFM as a Charge Microscopy MFM Contrast in the Presence of Perturbations Tip Stray Field Values Forces in the Case of Perturbation Perturbations in Patterned Permalloy Elements Conclusion and Perspectives 248 References Magnetic Force Microscopy - Towards Higher Resolution L. Abelmann, A. van den Bos, C. Lodder Principle of MFM Mode of Operation Instrumentation MFM in Magnetic Data Storage Research Limits of Resolution in MFM Critical Wavelength Thermal Noise Limited Resolution Tip-Sample Distance Control Tips Ideal Tip Shape Handmade Tips Coating of AFM Tips Tip Planes: The CantiClever Concept 279 References Scanning Probe Methods for Magnetic Imaging U. Hartmann General Strategies in Scanning Probe Microscopy Probe-Sample Interactions Suitable for Magnetic Imaging Scanning Near-Field Magneto-optic Microscopy Scanning SQUID Microscopy SQUID Basics Conventional Approaches Flux-Guided Scanning SQUID Microscopy Magnetic Resonance Force Microscopy Basic Concepts Global Experiments Mechanically Detected Magnetic Resonance As an Imaging Technique Conclusions and Outlook 304 References 305 Index 309