Kolloquiumsvortrag: PD Dr. Oleg Petracic, Forschungszentrum Juelich GmbH / 18.05.2015

18.05.2015 von 17:15 bis 18:45

Institut für Materialwissenschaft, Kaiser Str. 2, Geb.C , Raum "Aquarium"

Titel: Functional nanomaterials from self-assembled magnetic nanoparticles

 

 

Abstract:

Nanoparticles (NPs) can be considered as multi-functional 'building blocks' for novel materials with tunable physical and chemical properties. Magnetic NPs can be used e.g. for novel energy efficient data storage systems, spintronic devices or permanent magnets with improved properties. I will report on (1.) magnetic monomer NPs from FePt, MnO and iron oxide and (2.) heterodimer ('Janus') NPs consisting of a ferromagnetic (FM) FePt particle attached to an antiferromagnetic (AF) MnO particle. The monomer iron oxide NPs have a diameter of 15 or 20 nm. By applying them onto various substrates and also using various techniques, they form self-organized sub-monolayers, monolayers, multilayers or 3d supercrystals. The structure and magnetism of these assemblies has been investigated using grazing incidence small angle x-ray and neutron scattering, electron microscopy and magnetometry. In FePt@MnO heterodimer particle systems the close contact of the two subunits yields an exchange bias effect. The spin structure has been studied using neutron scattering.

Our results yield the perspective on how to tune the magnetic behavior of the individual building blocks on the one hand and the collective properties of the entire NP assembly on the other hand.

 References:

[1]       S. A. Claridge, A. W. Castleman, S. N. Khanna, C. B. Murray, A. Sen, and P. S. Weiss, ACS Nano 3, 244 (2009).

[2]       O. Petracic, Superlatt. Microstr. 47, 569 (2010).

[3]       S. Bedanta, A. Barman, W. Kleemann, O. Petracic, and T. Seki, Magnetic nanoparticles-
a subject for both fundamental research and applications,
J. Nanomater. 2013, 952540 (2013)

[4]       D. Mishra, D. Greving, G. A. Badini Confalonieri, J. Perlich, B.P. Toperverg, H. Zabel, and
O. Petracic, Growth modes of nanoparticle superlattice thin films, Nanotechnology 25, 205602 (2014)

[5]       S. Bedanta, O. Petracic, and W. Kleemann , Supermagnetism, Handbook of Magnetic Materials, Vol. 23, Ed. K.J.H. Buschow, Elsevier (2015)

 

 

 

 

 

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