Search results for "Magnetization"
showing 10 items of 550 documents
Hydrogen-like bismuth
1995
Atomic physics at heavy ion storage rings allows to study matter in an extreme ionization state and at very high velocity. The concept of electron cooling yields an ion beam with epithermal temperatures, which is suited for many precision experiments. At the ESR even the heaviest elements can be stored up to the fully stripped charge state. The H-like ions with nuclear spin exhibit a groundstate hfs-splitting in the optical region. This can be used as a probe for QED at high Z and magnetization inside the nucleus. The topics related to cooling of ions and laser spectroscopy in a storage ring are reported and a first result of the 1s hfs in 209Bi82+ is discussed for the relevance in testing …
Controlling the intralayer structure of Co/Pt superlattices
1999
Abstract The effect of the surface quality of MgO (1 1 1) substrates seeded by a 3 nm thick Pt layer on the intralayer and interlayer structure of Co/Pt (1 1 1) superlattices was investigated. The superlattices were grown by DC magnetron sputtering. Pre-growth processing of the MgO shows that intensive polishing using a specific H 2 O/SiO 2 suspension prior to growth is mandatory for obtaining long-range structural coherence in the films. The comparison between superlattices grown on re-polished and as-supplied substrates shows that the substrate treatment enhances the crystalline in-plane orientation and suppresses abc / acb twin formation. Magnetization measurements were performed using t…
Alkoxide-intercalated CoFe-layered double hydroxides as precursors of colloidal nanosheet suspensions: structural, magnetic and electrochemical prope…
2014
Alkoxide-intercalated CoFe-layered double hydroxides (CoFe–LDHs) were synthesized via the non-aqueous methanolic route. According to powder X-ray diffraction and field emission scanning electron microscopy, they exhibit a nanosized plate-like morphology with a basal space of 9.21 A. The hydrolysis of the material in water leads to colloidal suspensions of nanosheets with lateral dimensions of about 20 nm and thicknesses of ca. 4 nm as demonstrated by atomic force microscopy and dynamic light scattering. Atomic resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy confirm the high crystalline quality of the crystals and the proper Co/Fe stoichio…
Slow relaxation of the magnetization, reversible solvent exchange and luminescence in 2D anilato-based frameworks.
2020
A series of multifunctional 2D frameworks prepared with Dy(iii) and the bromanilato ligand, formulated as: [Dy2(C6O4Br2)3(G)n]·nG with G = H2O, dimethylformamide (dmf) and dimethylsulfoxide (dmso), can exchange the coordinated and non-coordinated solvent molecules (G) in a reversible way. These multifunctional frameworks show field induced slow relaxation of the magnetization and luminescence that can be easily and reversibly modified by solvent exchange.
Element-Selective Magnetic Imaging in Exchange-Coupled Systems by Magnetic Photoemission Microscopy
1998
We have used a photoemission microscope to obtain element-resolved magnetic contrast in stacked magnetic thin film systems. Magnetic information is thereby provided by X-ray magnetic circular dichroism. Elemental sensitivity, which is crucial for studying magnetic coupling phenomena in systems with several different layers, is achieved by tuning the energy of the illuminating photons to atomic absorption edges. We present measurements of a Ni-coated Co micropattern on Cu(001), and a wedged Co/Cr/Fe(001) sample. In the former sample the Ni magnetization is seen to follow the magnetization of the Co pattern, thereby changing from an out-of-plane easy axis in areas without underlying Co to in…
Direct imaging of delayed magneto-dynamic modes induced by surface acoustic waves.
2017
The magnetoelastic effect—the change of magnetic properties caused by the elastic deformation of a magnetic material—has been proposed as an alternative approach to magnetic fields for the low-power control of magnetization states of nanoelements since it avoids charge currents, which entail ohmic losses. Here, we have studied the effect of dynamic strain accompanying a surface acoustic wave on magnetic nanostructures in thermal equilibrium. We have developed an experimental technique based on stroboscopic X-ray microscopy that provides a pathway to the quantitative study of strain waves and magnetization at the nanoscale. We have simultaneously imaged the evolution of both strain and magne…
Current-Induced Skyrmion Generation through Morphological Thermal Transitions in Chiral Ferromagnetic Heterostructures.
2018
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Magnetic skyrmions promise breakthroughs in future memory and computing devices due to their inherent stability and small size. Their creation and current driven motion have been recently observed at room temperature, but the key mechanisms of their formation are not yet well-understood. Here it is shown that in heavy metal/ferromagnet heterostructures, pulsed currents can drive morphological transitions between labyrinth-like, stripe-like, and skyrmionic states. Using high-resolution X-ray microscopy, the spin texture evolution with temperature and magnetic field is imaged and it is demonstrated that with transient Joule heating, topologica…
Charge transfer and tunable minority band gap at the Fermi energy of a quaternaryCo2(MnxTi1−x)GeHeusler alloy
2010
We investigate the distribution of element-specific magnetic moments and changes in the spin-resolved unoccupied density of states in a series of half-metallic ${\text{Co}}_{2}({\text{Mn}}_{x}{\text{Ti}}_{1\ensuremath{-}x})\text{Ge}$ Heusler alloys using x-ray magnetic circular dichroism. The Co and Mn magnetic moments are oriented parallel while a small Ti moment shows antiparallel to the mean magnetization. The element-specific magnetic moments remain almost independent on the composition. Therefore, a replacement of Ti by Mn results in an increase in magnetization. The increase in magnetization with increasing $x$ follows the Slater-Pauling rule. The Fermi level decreases with respect to…
The influence of intergranular interaction on the magnetization of the ensemble of oriented Stoner-Wohlfarth nanoparticles
2008
We consider the influence of interparticle interaction on the magnetization reversal in the oriented Stoner-Wohlfarth nanoparticles ensemble. To do so, we solve a kinetic equation for the relaxation of the overall ensemble magnetization to its equilibrium value in some effective mean field. Latter field consists of external magnetic field and interaction mean field proportional to the instantaneous value of above magnetization. We show that the interparticle interaction influences the temperature dependence of a coercive field. This influence manifests itself in the noticeable coercivity at $T>T_{b}$ ($T_{b}$ is so-called blocking temperature). The above interaction can also lead to a forma…
Epitaxial films of the magnetic shape memory material
2007
Abstract By DC-sputtering from a stoichiometric target onto sapphire substrates we prepared epitaxial films of Ni 2 MnGa . X-ray diffraction in two circle geometry shows only the Ni 2 MnGa peaks corresponding to a (1 1 0) oriented growth on the (1 1 0) oriented sapphire substrate. Rocking curve scans shows that the out of plane orientation has a width of only 1 . 1 ∘ . By four circle X-ray diffraction we find an in-plane aligned growth. The Curie temperature as determined by SQUID magnetometry is 368 K. On cooling down the low field magnetization drops at around 260–280 K indicating the austenite to martensite transition. The presence of two different phases at high and low temperature also…