title: Von Nanosäulen, Ferromagneten und Piezoelektrizität: Nanoskalige magnetische Hybridsysteme
Creators: name: Wende, Heiko
Publisher: name: DuEPublico: Duisburg-Essen Publications online, University of Duisburg-Essen, Germany
Year: 2016
Subjects: subject: 530

description: Für die Anwendungen magnetischer Nanostrukturen im Alltag (Datenspeicherung, Kontrastmittel in der Kernspinresonanztomographie, Hyperthermie zur Tumorbehandlung, in Ferrofluiden in Lautsprechern) werden ganz unterschiedliche magnetische Eigenschaften benötigt. Heiko Wende untersucht diese in neuen nanoskaligen magnetischen Hybridsystemen.
description: Nanoscale magnetic hybrid systems
exhibit new fascinating properties
which pave the way to new applications:
ranging from new data
storage concepts and magneticallycontrolled
shock absorbers in cars
to hypothermia cancer treatment. In
this article some examples are given
of the ways in which these magnetic
hybrid systems can be constructed
by combination of different building
blocks such as magnetic molecules,
nanoparticles and ultrathin films.
To resolve the interesting magnetic
interactions, element-specific measurements
are carried out by X-ray
absorption spectroscopy at largescale
facilities, namely synchrotron
radiation sources. These provide an
insight into the magnetic behavior
of the individual components of the
hybrid systems. As the local atomic
properties are determined by these
experimental techniques, the results
can be easily compared to ab initio
calculations using density functional
theory. Thus, theory-based
predictions on the specific magnetic
interactions within the hybrid systems
can be directly tested in the
experiment. Therefore, experiment
and theory nicely complement each
other. This is discussed here, e.g. for the tailoring of the magnetic
coupling of rare earth and transition
metal layers in gadolinium/chromium/
iron layered structures. The
parallel coupling of the gadolinium
and the iron magnetic moments
reveal the potential of new magnets
high in moments for magnetic data
storage devices. Furthermore, the
modification of the magnetic anisotropy
of magnetic iron-platinum
nanoparticles embedded in a metallic
film is analyzed. The interplay
between experiment and theory
enabled the establishment of design
rules for the synthesis of nanoparticles
with properties required for
the individual applications. In addition,
the coupling of magnetic molecules
to thin ferromagnetic films is
presented. This coupling leads to the
ordering of the magnetic moments in
the molecule even at room temperature
with a magnetic memory effect
(magnetic hysteresis). As an example
of the interplay of a piezoelectric
system with a ferrimagnetic material,
a multiferroic nanocomposite is
investigated that consists of magnetic
nano columns embedded in a piezoelectric
surrounding. The elementspecific
measurements demonstrate
that a magneto-electric coupling
can indeed be determined for this
composite. This may be the starting
point for new data storage concepts.
description: UNIKATE: Berichte aus Forschung und Lehre, no. 48Materials Chain: Forschung aus dem UA Ruhr-Profilschwerpunkt, p. 90