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S e p t e m b e r 2 4 - 2 6 , 2 0 1 8 | B u d a p e s t , H u n g a r y
Magnetic Materials 2018
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Page 26
MAGNETISM AND
MAGNETIC MATERIALS
2nd International Conference on
Materials Science and Nanotechnology | Volume 2
OF EXCELLENCE
IN INTERNATIONAL
MEETINGS
YEARS
Wolfgang Kleemann, Mater Sci Nanotechnol 2018, Volume 2
MULTIFERROIC AND MAGNETOELECTRIC
NANOCOMPOSITES FOR DATA
PROCESSING
Switching of magnetism with electric fields and magnetic control of electric
polarization are challenging tasks for multiferroic andmagneto-electric ma-
terials. For data processing applications various composite realizations appear
most promising: We propose 2-2 nanocomposites based on magneto-electric
(ME) chromia (111) films (Cr2O3), which allow electric switching of the mag-
netization of epitaxially grown ultrathin ferromagnetic Co/Pt/Co trilayers via
inter-facial exchange bias. Random access memory (ME-RAM) and logic cell
MEXOR have been approved. Regular composites of magnetostrictive cobalt
ferrite (CoFe2 O4) nanopillars are PLD-grown in a piezoelectric film of barium
titanate (BaTiO3). In a transverse magnetic field, they exert a staggered shear
stress-induced surface pola¬ri-za¬tion pattern in the BaTiO3 environment.
Possible data storage applications will be discussed. Ceramic 0-3 compos-
ites of antiferromagnetic-ferroelectric Bi (Fe,Co)O3 nanoclusters embedded
in K0.5Bi0.5TiO3 reveal giant linear magneto-electric response via bilinear
piezo-magneto-electric coupling, M=αE with α»10-5 s/m. They are candidates
for future electrically addressable nanodot mass memory devices.
Fig.1: Magnetoelectric (ME) write head for magnetic hard disk. An electric field
E gene-rates magnetic moment ΔmME in a ME material, thus giving rise to
magnetic flux density B. A gap in the flux closing yoke emits a stray field, which
writes a magnetic bit into the moving hard disk.
Recent Publications
1. Kleemann W (2009). Switching magnetism with electric fields. Physics 2: 105-6.
2. Borisov B et al. (2006). Magnetoelectric Switching of Exchange Bias. Phys. Rev.
Lett. 94:117293.
3. Schmitz-Antoniak C et al. (2013). Electric polarization in nano-composites tuned
by magnetic field. Nature Commun. 4:2051.
4. Henrichs LF et al. (2016). Multiferroic clusters. Advan. Funct. Mater. 26: 2111-
2121.
Biography
Wolfgang Kleemann has completed his PhD at
Goettingen University, Germany. After postdoc re-
search at Université Paris-Sud, Orsay, and University
of California, Santa Barbara, he became full Profes-
sor of University Duisburg-Essen, Germany, in 1982.
His actual main research fields are magnetism,
ferroelectricity, multiferroics and magnetoelectrics.
His more than 450 publications have achieved over
12,000 citations at h-index 47. He has been serving
in editorial boards of reputed journals and organiza-
tion committees of various conference series.
wolfgang.kleemann@uni
Wolfgang Kleemann
University Duisburg-Essen, Germany