Dr. Kilian Lenz

Research Group Head
Phone: +49 351 260 2435
Fax: +49 351 260 12435

Hybrid Magnetic Materials:

microscopic origin – macroscopic results

Supported by DFG grant: FA 314/3-1


Prof. Dr. Jeffrey McCord (Universität Kiel)

Dr. Jörg Raabe (Swiss Light Source, Villigen)

Dr. Stephen McVitie (Univ. Glasgow)

Dr. Peter Fischer (Center for X-ray Optics, Advanced Light Source, Berkeley)


The correlation between artificially generated magnetic domain configurations and effective magnetic properties, i. e., magnetic anisotropy, exchange coupling and interlayer exchange coupling, is investigated. The artificial domain structures are created by means of ion irradiation techniques, which allow a modification of the magnetic parameters on a length scale similar to or even below the exchange correlation length (typically ~ 10 – 1000 nm). Thereby completely new domain walls and domain configurations, which are not possible in conventional thin films, are created. With further miniaturization the domains vanish and an „effective“ material with new properties, neither observed in fully irradiated nor in the non-irradiated films. These are so-called hybrid materials.

First, the basic understanding of simple model systems, as for example at the transition between to different areas with different magnetic parameters, quasi two dimensional structures or magnetic point defects, is the goal. In a second step the functional relation between microscopic patterns and integral magnetic properties is investigated.


Hybrid Sketch Hybrid Kerr

Sketch of a local Cr implantation in a permalloy film.

a), b): Parallel to the stripe axis demagnetized state;
c), d) different domain configurations during magnetization reversal
e) and f) domain configuration in remanence and close to coercivity, in print


Jürgen Fassbender
Monika Fritzsche
Julia Osten
Manuel Langer
Kilian Lenz
Anja Banholzer
Andreas Neudert
Thomas Strache

Review article

Introducing artificial lenth scales to tailor magnetic properties
J. Fassbender, T. Strache, M. O. Liedke, D. Markó, S. Wintz, K. Lenz, A. Keller, S. Facsko, I. Mönch, J. McCord
New J. Phys., in press.

Magnetic patterning by means of ion irradiation and implantation
J. Fassbender, J. McCord
J. Magn. Magn. Mater., 320, 579 (2008).

Tailoring Magnetism by Light Ion Irradiation
J. Fassbender, D. Ravelosona, Y. Samson
J. Phys. D: Applied Physics 37, R179 (2004).


Spin reorientation transititions in Pt/Co/Pt films under low dose Ga+ ion irradiation
J. Jaworowicz, A. Maziewski, P. Mazalski, M. Kisielewski, I. Sveklo, M. Tekielak, V. Zablotskii, J. Ferre, N. Vernier, A. Mougin, A. Henschke, J. Fassbender
Appl. Phys. Lett. 95, 022502 (2009).

Improvement of structural, electronic and magnetic properties of Co2MnSi thin films by He+-irradiation
O. Gaier, J. Hamrle, B. Hillebrands, M. Kallmayer, P. Pörsch, G. Schönhense, H. J. Elmers, J. Fassbender,  A. Gloskovskii, C. A. Jenkins, C. Felser, E. Ikenaga, Y. Sakuraba, S. Tsunegi, M. Oogane, Y. Ando
Appl. Phys. Lett. 94, 152508 (2009).

Local stress engineering of magnetic anisotropy in soft magnetic thin films
N. Martin, J. McCord, A. Gerber, T. Strache, T. Gemming, I. Mönch, N. Farag, R. Schäfer, J. Fassbender, E. Quandt, L. Schultz
Appl. Phys. Lett. 94, 062506 (2009).

Influence of Cr-ions on the magnetic behaviour of FeCo films
R. Gupta, R. Ansari, A. Khandelwal, J. Fassbender, A. Gupta
Nucl. Instr. Meth. B. 266, 1407 (2008).

Hybrid soft-magnetic films with novel functionality created by magnetic property patterning
J. McCord, L. Schultz, J. Fassbender
Advanced Materials 20, 2090 (2008); Cover Image; Press Release.

Control of saturation magnetization, anisotropy and damping due to Ni implantation in thin Ni81Fe19 films
J. Fassbender, J. McCord
Appl. Phys. Lett. 88, 252501 (2006).

Structural and magnetic modifications in Cr implanted Permalloy
J. Fassbender, J. von Borany, A. Mücklich, K. Potzger, W. Möller, J. McCord, L. Schultz, R. Mattheis
Phys. Rev. B 73, 184410 (2006).

Magnetic domains and magnetization reversal of ion-induced magnetically patterned RKKY-coupled Ni81Fe19/Ru/Co90Fe10 films
J. Fassbender, L. Bischoff, R. Mattheis, P. Fischer
J. Appl. Phys. 99, 08G301(2006).

Magnetic anisotropy and domain patterning of amorphous films by He-ion irradiation
J. McCord, T. Gemming, L. Schultz, J. Fassbender, M. O. Liedke, M. Frommberger, E. Quandt
Appl. Phys. Lett., 86, 162502 (2005).

On the mechanism of ion irradiation enhanced exchange bias
S. Poppe, J. Fassbender, B. Hillebrands

Control of interlayer exchange coupling in Fe/Cr/Fe trilayers by ion beam irradiation
S. O. Demokritov, C. Bayer, S. Poppe, M. Rickart, J. Fassbender, B. Hillebrands, D. I. Kholin, N. M. Kreines, O. M. Liedke
Phys. Rev. Lett. 90, 097201 (2003).

Local manipulation and reversal of the exchange bias field by ion irradiation in FeNi/FeMn double layers
A. Mougin, T. Mewes, M. Jung, D. Engel, A. Ehresmann, H. Schmoranzer, J. Fassbender, B. Hillebrands
Phys. Rev. B 63, 060409(R) (2001)

Suppression of exchange bias by ion irradiation
T. Mewes, R. Lopusnik, J. Fassbender, B. Hillebrands, M. Jung, D. Engel, A. Ehresmann, H. Schmoranzer
Appl. Phys. Lett. 76, 1057 (2000).