Speaker
Ms
Ana Maria Balan
(Swiss Light Source, Paul Scherrer Institut)
Description
Increasing the storage density in future magnetic memory devices to the ultimate limit will require to address information at the level of individual nanoparticles. However, at small sizes thermal excitations can lead to undesired fluctuations of the magnetization and will affect their response to magnetic fields. In this contribution we use photoemission electron microscopy (PEEM) together with x-ray magnetic circular dichroism (XMCD) to detect the magnetization of individual Fe nanoparticles at room temperature. By varying the particle size we observe the transition from the superparamagnetic state to stable ferromagnetism at a particle size of about 12 nm. Applying a magnetic field allows us to record magnetization curves of the particles in both states and in the transition regime. The data are compared to the predictions of simple macro spin models. The role of non-collinear spin structures on the mechanism of the thermally induced magnetization reversal is also discussed.
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poster
Please specify the session
Imaging
Primary author
Ms
Ana Maria Balan
(Swiss Light Source, Paul Scherrer Institut)
Co-authors
Dr
Arantxa Fraile Rodríguez
(Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona)
Dr
Armin Kleibert
(Swiss Light Source, Paul Scherrer Institut)
Prof.
Frithjof Nolting
(Swiss Light Source, Paul Scherrer Institut)
Dr
Joachim Bansmann
(Institute of Surface Chemistry and Catalysis, University of Ulm)
