0000000000672125
AUTHOR
Paul J. Ziemann
Ptychographic imaging and micromagnetic modeling of thermal melting of nanoscale magnetic domains in antidot lattices
CA extern Antidot lattices are potential candidates to act as bit patterned media for data storage as they are able to trap nanoscale magnetic domains between two adjacent holes. Here, we demonstrate the combination of micromagnetic modeling and x-ray microscopy. Detailed simulation of these systems can only be achieved by micromagnetic modeling that takes thermal effects into account. For this purpose, a Landau-Lifshitz-Bloch approach is used here. The calculated melting of magnetic domains within the antidot lattice is reproduced experimentally by x-ray microscopy. Furthermore, we compare conventional scanning transmission x-ray microscopy with resolution enhanced ptychography. Hence, we …
Vibrations of a single adsorbed organic molecule: anharmonicity matters!
Vibrational spectroscopy is a powerful tool to identify molecules and to characterise their chemical state. Inelastic electron tunnelling spectroscopy (IETS) combined with scanning tunnelling microscopy (STM) allows the application of vibrational analysis to a single molecule. Up to now, IETS was restricted to small species due to the complexity of vibration spectra for larger molecules. We extend the horizon of IETS for both experiment and theory by measuring the STM-IETS spectra of mercaptopyridine adsorbed on the (111) surface of gold and comparing it to theoretical spectra. Such complex spectra with more than 20 lines can be reliably determined and computed leading to completely new ins…
Electronic and Magnetic Properties of Ligand-Free FePt Nanoparticles
Ligand-free FePt nanoparticles are prepared in densely packed arrays (see Figure) under ultrahigh vacuum conditions, in which oxygen and hydrogen plasmas are used to remove the organic shells that are present after particle synthesis. The electronic structure and magnetic properties of the “bare”, face-centered-cubic FePt particles are presented. Applications in high-density magnetic data recording are foreseen.