13 research outputs found
Hysteresis-free magnetization reversal of exchange-coupled bilayers with finite magnetic anisotropy
Exchange-coupled structures consisting of ferromagnetic and ferrimagnetic
layers become technologically more and more important. We show experimentally
the occurrence of completely reversible, hysteresis-free minor loops of [Co(0.2
nm)/Ni(0.4 nm)/Pt(0.6 nm)] multilayers exchange-coupled to a 20 nm thick
ferrimagnetic TbCoFe layer, acting as hard magnetic
pinning layer. Furthermore, we present detailed theoretical investigations by
means of micromagnetic simulations and most important a purely analytical
derivation for the condition of the occurrence of full reversibility in
magnetization reversal. Hysteresis-free loops always occur if a domain wall is
formed during the reversal of the ferromagnetic layer and generates an
intrinsic hard-axis bias field that overcomes the magnetic anisotropy field of
the ferromagnetic layer. The derived condition further reveals that the
magnetic anisotropy and the bulk exchange of both layers, as well as the
exchange coupling strength and the thickness of the ferromagnetic layer play an
important role for its reversibility.Comment: 9 pages, 7 figure
In-Situ TOF-SIMS and SFM Measurements Providing True 3D Chemical Characterization of Inorganic and Organic Nanostructures
Scanning Probe Microscopy: The Lab on a Tip
Explains all essential aspects of scanning probe microscopy, including STM and AFM techniques Serves as an ideal accompaniment to courses at the graduate and advanced undergraduate levels Presents state-of-the-art scientific results based on the latest research Covers a range of other SPM technique
Atomic contact potential variations of Si(111)-7 * 7 analyzed by Kelvin probe force microscopy
We studied atomic contact potential variations of Si(111)-7 x 7 by Kelvin probe force microscopy with the amplitude modulation technique at the second resonance of a silicon cantilever. Enhanced sensitivity due to the high mechanical quality factor in ultra-high vacuum enabled local contact potential difference (LCPD) measurements of individual adatoms. The contrast of the measured LCPD map became stronger by reducing the tip-sample distance, and the averaged LCPD value shifted to more negative. The short-range interaction, arising from the covalent bonding interactions, strongly affects the LCPD measurement. Theoretical calculations indicate that the amplitude modulation method has a higher sensitivity than the frequency modulation method in practical cases. The tip-sample distance dependence of LCPD was investigated by numerical calculations
Microscopic origin of magnetization reversal in nanoscale exchange-coupled ferri/ferromagnetic bilayers: implications for high energy density permanent magnets and spintronic devices
SFM Assisted In-Situ by ToF-SIMS: Accessing Chemical Information in True Three Dimensions
2024 Roadmap on Magnetic Microscopy Techniques and Their Applications in Materials Science
Considering the growing interest in magnetic materials for unconventional computing, data storage, and sensor applications, there is active research not only on material synthesis but also characterisation of their properties. In addition to structural and integral magnetic characterisations, imaging of magnetization patterns, current distributions and magnetic fields at nano- and microscale is of major importance to understand the material responses and qualify them for specific applications. In this roadmap, we aim to cover a broad portfolio of techniques to perform nano- and microscale magnetic imaging using SQUIDs, spin center and Hall effect magnetometries, scanning probe microscopies, x-ray- and electron-based methods as well as magnetooptics and nanoMRI. The roadmap is aimed as a single access point of information for experts in the field as well as the young generation of students outlining prospects of the development of magnetic imaging technologies for the upcoming decade with a focus on physics, materials science, and chemistry of planar, 3D and geometrically curved objects of different material classes including 2D materials, complex oxides, semi-metals, multiferroics, skyrmions, antiferromagnets, frustrated magnets, magnetic molecules/nanoparticles, ionic conductors, superconductors, spintronic and spinorbitronic materials.ISSN:2515-763