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 15.52: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Blocking temperature distribution of magnetically diluted exchange biased systems — •Marian Fecioru-Morariu, Mohammad Reza Ghadimi, Bernd Beschoten, and Gernot Güntherodt — Physikalisches Institut (IIA), RWTH Aachen, 52056 Aachen, Germany
We have systematically investigated the blocking temperature distribution (BTD) of two different exchange bias systems: the epitaxial system Co(111)/Co1−y O(111) with the insulating high-anisotropy antiferromagnet (AFM) CoO and the polycrystalline system CoFe/(IrMn)1−xCux with the metallic intermediate-anisotropy AFM IrMn. The effects of Co deficiencies in Co1−y O and of nonmagnetic Cu defects in (IrMn)1−xCux on the exchange bias field (HEB) and BTD are analyzed by reversing the AFM domains at successively higher temperatures in the reverse cooling fields. For both systems, the nonmagnetic defects give rise to an enhancement of HEB. Additionally, a broadening of the BTD is observed for the system Co1−y O. For the AFM IrMn, with increasing Cu dilution, the AFM grain size decreases and therefore the BTD shifts to lower temperatures. The BTD is correlated with the domain and grain size distribution within the AFM. Further influences of dilution, temperature, time and reversal fields on HEB and BTD will be discussed. We acknowledge the financial support from NEXBIAS Research Training Network (Contract No. HPRN-CT-2002-00296) financed by the EU.