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Magnetism of Thin Films and Heterostructures

English title Magnetism of Thin Films and Heterostructures
Applicant Hug Hans Josef
Number 117970
Funding scheme Project funding (Div. I-III)
Research institution Departement Physik Universität Basel
Institution of higher education University of Basel - BS
Main discipline Condensed Matter Physics
Start/End 01.10.2007 - 31.03.2010
Approved amount 367'825.00
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Keywords (14)

Magnetism; Thin Film; Heterostructures; Exchange-bias effect; Magnetic Memory; Strain incuced Magnetic Anisotropy; Exchange bias effect; uncompensated spins; training effect; return and complimentary point; high resolution magnetic imaging; magnetic force microscopy; magnetometry; sputter deposition

Lay Summary (English)

Lead
Lay summary
The goals of this proposal is the study of a selected variety of magnetic thin film and hetero-structure samples. Among these are multilayers of ferromagnetic, antiferromagnetic and non magnetic materials that exhibit an exchange bias effect (EB-effect). Although considerable experimental and theoretical efforts have been invested, the role of the pinned uncompensated spins (UCS), the microscopic mechanisms generating these UCS, their stability upon field-cycles and the materials science to enhance the EB-effect is still under controversial discussion. We have recently shown that high resolution, low temperature magnetic force microscopy (LTMFM) and quantitative magnetic force microscopy data analysis are powerful new experimental tools to image and quantify UCS. Our recent experiments revealed that two distinct groups of UCS co-exist and that one plays a dominant role for the EB-effect. New experiments planned in this proposal address the spatial distribution of the UCS on the length scale of the grains of the antiferromagnetic material and the mechanisms generating the UCS. New routes for the enhancement of the EB-effect will be explored. Further experiments aim at an improved microscopic understanding of the training effect. EB-samples will be designed and fabricated to allow for an optimized quantitative MFM data analysis. As a second topic magnetic memory and particularly microscopic magnetic return and complimentary point memory (RPM and CPM) will be studied. Key questions to be answered are the mechanisms that lead RPM and CPM, how RPM and CPM are lost after domain nucleation during domain growth and why CPM is lower than RPM. This work again requires the fabrication of samples with dedicated defects. To date, RPM and CPM were only studies in Fourier space. In preliminary experiments we have already shown that direct space imaging can easily give answers to relevant questions with high statistical confidence. The study of domain evolution mechanisms clearly require direct space techniques.The work profits from a unique combination of experimental tools available at the Department of Physics at the University of Basel and the Laboratory for Nanoscale Materials Science at Empa Dübendorf. Heterostructure samples designed for an optimized quantitative MFM data analysis will be prepared and macroscopically characterized at Empa. Magnetic Force Microscopy and quantitative data analysis will be performed at the University of Basel.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Associated projects

Number Title Start Funding scheme
130519 Magnetism of Thin Films and Heterostructures 01.04.2010 Project funding (Div. I-III)
130519 Magnetism of Thin Films and Heterostructures 01.04.2010 Project funding (Div. I-III)
147084 Magnetism of Coupled Ferromagnetic and Rare-earth Ferrimagnetic Thin Films 01.06.2013 Project funding (Div. I-III)
113496 Neue Einsichten in die Sonden-Proben-Wechselwirkung bei den Rastersondenmethoden 01.10.2006 Project funding (Div. I-III)

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