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Univ. Paris-Saclay
Measuring spin dynamics in Nanoscale Volumes
P. Chris Hammel - Department of Physics, Ohio State University, Columbus, OH USA
Mercredi 01/08/2012, 11:00
SPEC Salle Itzykson, Bât.774, Orme des Merisiers

Scanned probe magnetic resonance is enabling new methods for studying spin dynamics in small structures. We will present scanned probe electron spin resonance measurements of nanostructured volumes of diamond containing nitrogen impurities. We find unexpected sensitivity of spin dynamics on the volume probed by the experiment.

Scanned probe ferromagnetic resonance imaging (FMRI) is a novel magnetic imaging technique based on Magnetic Resonance Force Microscopy. FMRI offers the ability to image nanoscale properties of buried ferromagnets; a particular and unique strength is its ability to map internal fields with spectroscopic precision. We present measurements of the spatial variation of the internal exchange bias and other fields in a ferromagnetic film in a patterned sample in which the orientation of the exchange bias field has been locally reversed by He ion bombardment. We find that the abrupt change in internal field at the reversal boundary is sufficient to localize the FMR mode, producing a mode confined by the superposition of the probe field and the internal field step. This model effectively describes the observed field shifts when the probe is scanned across the stripe boundary.

Supported by the U.S. DOE through Grant No. DE-FG02-03ER46054 and by the NSF through Grant No. 0820414.



1. "Local Ferromagnetic Resonance Imaging with Magnetic Resonance Force
Microscopy," PRL vol 100, 197601 (2008).

2. "Nanoscale scanning probe ferromagnetic resonance imaging using localized
modes." Nature vol. 466, pp. 845-848 (12 August 2010) doi:10.1038/nature09279.


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