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FIRB “Microsistemi e Nanomateriali Magnetici” Tematica T4 “Films e Multistrati” Nanocompositi Magnetici Multistrato Labo

FIRB “Microsistemi e Nanomateriali Magnetici” Tematica T4 “Films e Multistrati” Nanocompositi Magnetici Multistrato Laboratorio “Superfici” M. Carbucicchio, M. Rateo, M. Prezioso, F. Zini Dipartimento di Fisica – Università di Parma. Collaborazioni :. G. Asti, M. Ghidini, M. Solzi

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FIRB “Microsistemi e Nanomateriali Magnetici” Tematica T4 “Films e Multistrati” Nanocompositi Magnetici Multistrato Labo

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  1. FIRB “Microsistemi e Nanomateriali Magnetici” Tematica T4 “Films e Multistrati” Nanocompositi Magnetici Multistrato Laboratorio “Superfici” M. Carbucicchio, M. Rateo, M. Prezioso, F. Zini Dipartimento di Fisica – Università di Parma Collaborazioni: G. Asti, M. Ghidini, M. Solzi Laboratorio “Magnetometria” Dip. Fisica, Università, Parma A. Paoluzi, G. Turilli Laboratorio IMEM CNR, Parma Steve Bennett Department of Synchrotron Radiation Daresbury Laboratory Warrington, UK Frank J. Berry Department of Chemistry The Open University Milton Keyness, UK Michel Labrune Laboratoire PMTM-CNRS Université Paris-13 Villetaneuse, France

  2. Ultra-High Vacuum Growth by Electron Beams Vacuum: Starting10-8 Pa Operating 10-6 Pa Deposition Rate: 0.5 ÷ 0.8 nm/min Substrates: Amorphous Quartz Si(100), Si(111) no native oxide removal

  3. Materials: 1.Model System Co/Fe + Co Multilayers Co: 5.0 ÷ 15.0 nm Fe 0.5 ÷ 45.0 nm 2.RE-TM Systems Co/NdFeB/Co + Mo Nd2Fe14B arc evaporated 5[SmCo/Fe] + SmCo + Au SmCo5arc evaporated 3[SmCo/Co] SmCo5 from 10[Sm0.3/Co0.5] Co/SmCo5/Co SmCo5 co-evaporated Characterization: Auger Electron Spectroscopy Layer Thickness, Very Low Contamination Grazing Incidence X-Ray Diffraction (SRS Daresbury, UK) Crystallographic Structure, Textures, Grain Sizes Grazing Incidence X-Ray Reflection (SRS Daresbury, UK) Thickness, Density, Interface Roughness Atomic Force Microscopy Morphology of Surfaces Transmission Electron Microscopy (Erlangen, DE) Morphology of Multilayers and Interfaces Conversion Electron Mössbauer Spectroscopy Composition and Dimensions of Interfaces Direction of Magnetization Magnetic Force Microscopy Magnetic Domains

  4. Model System: simple materials soft/hard ratio = 3 In-plane AGFM Hysteresis Loops (IMEM) Interaction-based deviation parameter MR = saturation remanence IIRM(H) = isothermal remanence IDCD(H) = dc demagnetization remanence M > 0  positive exchange coupling (ferromagnetic interaction)

  5. Interface Analysis: CEMS Pure Iron Interfaces  Hhf distribution: - main peak (35 T) narrow linewidth  similar sublattices  sharp Fe concentration gradient - small peak (32 T) broad linewidth  a few Fe into Co

  6. Magnetic Anisotropy AGFM Hysteresis Loops (IMEM) Co5nm/Fe2nm For Fe layer thickness up to 24 nm Strong Uniaxial Magnetic Anisotropy Hard Axis Low Hysteresis (Mr/Ms 0) Easy Axis High Squareness (Mr/Ms 1) Remanence ratio Mr/Ms vs the in-plane applied magnetic field angle 180° periodicity with |sin| behaviour Anisotropy constant K1 (1.77  7.63)  104 erg/cm3

  7. CEMS MFM Fe layer thickness: < 5 nm in-plane magnetization 5  24 nm out-of-plane ~10° > 24 nm out-of-plane ~40° No stray fields Stretched domains Stripe domains

  8. First Endeavors: RE-TM Hard Layer AGFM Hysteresis Loop (IMEM) Problems: - Uncoupled Phases - Low Coercive Field - Composition

  9. AGFM Hysteresis Loop (IMEM) Single Phase Magnetic Behaviour CEMS for 5[SmCo/Fe] + SmCo + Au Problems: - Stoichiometry - Reproducibility - Interdiffusion (GIXRR, CEMS)

  10. AGFM Hysteresis Loop (IMEM) Synchrotron Radiation GIXRD Pattern Single Phase Magnetic Behaviour Low Coercive Field: Nanostructuration SmCo5 Stoichiometry

  11. Future Activities Ultra-High Vacuum Electron Beam Deposition of - RE-TM Films with High Coercive Fields - RE-TM/Fe Bilayers and Multilayers AFM and MFM observations - Morphology - Magnetic Domains CEMS - Composition and Dimensions of Interfaces - Direction of Magnetization Synchrotron Radiation GIXRD - Phase Composition - Grain Size, Textures - Kind and Intensities of Stresses - Depth-profiling: different X-ray incidence angles TEM and HEED Analyses both in plane and in cross-section - Morphology, Defectivity - Continuity, Thickness of layers - Grain Sizes, Crystallographic textures - Phase Composition Mapping - Roughness, Interdiffusion, Dimensions of Interfaces

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