Domain wall transformations and hopping in La0.7Sr0.3MnO3nanostructures imaged with high resolution x-ray magnetic microscopy

2014

We investigate the effect of electric current pulse injection on domain walls in La(0.7)Sr(0.3)MnO(3) (LSMO) half-ring nanostructures by high resolution x-ray magnetic microscopy at room temperature. Due to the easily accessible Curie temperature of LSMO, we can employ reasonable current densities to induce the Joule heating necessary to observe effects such as hopping of the domain walls between different pinning sites and nucleation/annihilation events. Such effects are the dominant features close to the Curie temperature, while spin torque is found to play a small role close to room temperature. We are also able to observe thermally activated domain wall transformations and we find that,…

Automatable sample fabrication process for pump-probe X-ray holographic imaging

2014

Soft X-ray holography is a recently developed imaging technique with sub-50 nm spatial resolution. Key advantages of this technique are magnetic and elemental sensitivity, compatibility with imaging at free electron laser facilities, and immunity to in-situ sample excitations and sample drift, which enables the reliable detection of relative changes between two images with a precision of a few nanometers. In X-ray holography, the main part of the experimental setup is integrated in the sample, which consequently requires a large number of fabrication steps. Here we present a generic design and an automatable fabrication process for samples suitable, and optimized for, efficient high resolut…

Dynamics and inertia of skyrmionic spin structures

2015

Understanding the motion of magnetic skyrmions is essential if they are to be used as information carriers in devices. It is now shown that topological confinement endows the skyrmions with an unexpectedly large mass, which plays a key role in their dynamics.

The effect of magnetic anisotropy on the spin configurations of patterned La(0.7)Sr(0.3)MnO3 elements.

2013

We study the effect of magnetocrystalline anisotropy on the magnetic configurations of La0.7Sr0.3MnO3 bar and triangle elements using photoemission electron microscopy imaging. The dominant remanent state is a low energy flux-closure state for both thin (15 nm) and thick (50 nm) elements. The magnetocrystalline anisotropy, which competes with the dipolar energy, causes a strong modification of the spin configuration in the thin elements, depending on the shape, size and orientation of the structures. We investigate the magnetic switching processes and observe in triangular shaped elements a displacement of the vortex core along the easy axis for an external magnetic field applied close to t…

Magnetic Anisotropy Engineering in Thin Film Ni Nanostructures by Magnetoelastic Coupling

2014

The effect of magnetocrystalline anisotropy on the domain structure of patterned Fe2CrSi Heusler alloy thin films

2013

The effects of magnetic anisotropy on domain structures in half-metallic Heusler alloy Fe2CrSi thin film elements were investigated using high resolution x-ray magnetic circular dichroism photoemission electron microscopy. The transition of the dominating contribution from the magnetocrystalline anisotropy to the shape anisotropy is observed in square-shaped elements when reducing the size below 2.0–2.5 μm. In particular, we identify in disk-shaped Heusler elements the vortex state as the ground state. The shape-anisotropy dominated, well-defined magnetization configuration shows the potential of the Fe2CrSi Heusler alloy for applications in vortex-core- or domain-wall-devices, where the hi…

ELECTRICAL-FIELD CONTROL OF MAGNETISM MEDIATED BY STRAIN IN Ni NANOSTRUCTURES FABRICATED ON PRE-POLED PMN–PT (011)

2013

We investigate the effects of piezoelectric-generated strain on the magnetization configuration of Ni nanostructures fabricated on pre-poled piezoelectric (011) [ Pb ( Mg 0.33 Nb 0.66) O 3]0.68–[ PbTiO 3]0.32 (PMN–PT) by high resolution X-ray microscopy. We observe a strong uniaxial anisotropy in the Ni nanostructures, due to the relaxation of the substrate following the deposition of the Ni . The anisotropy can be modified by the application of an electric field to the piezoelectric substrate (thus generating a piezoelectric strain in the system) through the magneto-elastic effect. By applying an electric field to the PMN–PT, the magnetization configuration in nanostructured Ni squares an…