Bottom-Up Synthesis of Metallic CoNi Nanoplatelets with Magnetic Vortex-Like Spin Configurations.

Magnetic nanoplatelets hold significant potential for various technical applications due to their ability to switch between a fully magnetized state with high magnetization and a vortex-like configuration that eliminates stray fields in the absence of an external field. This study presents the synthesis of uniform CoNi nanoplatelets through the topotactic reduction of metal hydroxides using hydrogen plasma. The reduction process is analyzed via magnetometry, leveraging the transition from paramagnetic hydroxide to ferromagnetic metal.

Acquisition of object and temperature series in medium resolution off-axis electron holography with live drift correction.

Collecting and averaging large datasets is a common practice in transmission electron microscopy to improve the signal-to-noise ratio. Averaging data in off-axis electron holography requires automated tools capable of correcting both the drift of the interference fringes and the drift of the specimen. This can be achieved either off-line, by post-processing hologram series, or on-line, through real-time microscope control.

Element-specific visualization of dynamic magnetic coupling in a Co/Py bilayer microstructure.

We present the element-specific and time resolved visualization of uniform ferromagnetic resonance excitations of a Permalloy (Py) disk-Cobalt (Co) stripe bilayer microstructure. The transverse high frequency component of the resonantly excited magnetization is sampled in the ps regime by a combination of ferromagnetic resonance (FMR) and scanning transmission X-ray microscopy (STXM-FMR) recording snapshots of the local magnetization precession of Py and Co with nanometer spatial resolution. The approach allows us to individually image the resonant dynamic response of each element, and we find that angular momentum is transferred from the Py disk to the Co stripe and vice versa at their respective resonances.

Continuous illumination picosecond imaging using a delay line detector in a transmission electron microscope.

Progress towards analysing transitions between steady states demands improvements in time-resolved imaging, both for fundamental research and for applications in information technology. Transmission electron microscopy is a powerful technique for investigating the atomic structure, chemical composition and electromagnetic properties of materials with high spatial resolution and precision. However, the extraction of information about dynamic processes in the ps time regime is often not possible without extensive modification to the instrument while requiring careful control of the operation conditions to not compromise the beam quality.

Towards laser printing of magnetocaloric structures by inducing a magnetic phase transition in iron-rhodium nanoparticles.

The development of magnetocaloric materials represents an approach to enable efficient and environmentally friendly refrigeration. It is envisioned as a key technology to reduce CO emissions of air conditioning and cooling systems. Fe-Rh has been shown to be one of the best-suited materials in terms of heat exchange per material volume.

Dynamic unidirectional anisotropy in cubic FeGe with antisymmetric spin-spin-coupling.

Strong unidirectional anisotropy in bulk polycrystalline B20 FeGe has been measured by ferromagnetic resonance spectroscopy. Such anisotropy is not present in static magnetometry measurements. B20 FeGe exhibits inherent Dzyaloshinskii-Moriya interaction, resulting in a nonreciprocal spin-wave dispersion.

Biologically encoded magnonics.

Spin wave logic circuits using quantum oscillations of spins (magnons) as carriers of information have been proposed for next generation computing with reduced energy demands and the benefit of easy parallelization. Current realizations of magnonic devices have micrometer sized patterns. Here we demonstrate the feasibility of biogenic nanoparticle chains as the first step to truly nanoscale magnonics at room temperature.