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Measurement of Mechanical Properties of Nanoscaled Ferrites using Atomic Force Microscopy at Ultrasonic Frequencies



Tsakalakos, T.; Kear, B.; Siegel, R.:
The Fourth International Conference on Nanostructured Materials (NANO '98)
Oxford: Pergamon Press, 1999 (Nanostructured materials 12.1999)
ISSN: 0965-9773
International Conference on Nanostructured Materials <4, 1998, Stockholm>
Conference Paper
Fraunhofer IZFP ()
Atomic Force Acoustic Microscopy; mechanical property

To measure local elasticity by atomic Force Acoustic Microscopy (AFAM), the sample placed in a commerical AFM is insonified by ultrasonic waves or the cantilever is oscillated at ultrasonic frequencies. In contact with the specimen, the cantilever-tip system vibrates out-of-plane and its resonances are measured. A quantitative model based on linear tip-sample force shows that the stiffness of the specimen can be derived from the shift of the contact resonance frequencies relative to resonance frequencies of the free cantilever. We report AFAM results with a well-known material, silicon single-crystal oriented in <100> direction, to prove the consistence of the local measurement of elasticiy. Then, in thin films of magnetite Fe3O4 and maghenite yFe2O3 with spinel structure, the influence of the deviation from the stoichiometry on the elasticity for a given grain size is determined.