Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)

MA 15.67: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

Magnetization dynamics in interlayer exchange coupled NiFe/Ru/NiFe thin films at high excitation amplitudes — •Tobias Martin, Mohamed Belmeguenai, Markus Maier, Georg Woltersdorf, and Günther Bayreuther — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg

The technological applications of interlayer exchange coupling are manifold, e.g. to bias GMR and TMR elements in read heads of hard disk drives. Furthermore it is used to produce synthetic antiferromagnets acting as soft layers in toggle MRAM cells. In order to further increase the data rates in such applications, it is of importance to understand the dynamic magnetization motion.

Here, coupled NiFe/Ru/NiFe film systems with varying Ru thickness are examined with static and dynamic techniques. The static characterization and determination of coupling constants is done by means of magneto optic Kerr effect and vibrating sample magnetometer. The precessional motion is investigated with a pulsed inductive microwave magnetometer (PIMM) and with vector network analyser FMR (VNA-FMR). The PIMM allows for excitation pulse fields of up to 150 Oe. Both dynamic techniques show optic and acoustic modes, although the VNA-FMR method was able to excite both modes simultaneously over a larger bias field range. At high excitation amplitudes additional pulse field dependent modes were observed. A large part of the modes can be explained by simulations using the simple macrospin model, which also helped to identify optical and acoustical mode.