Dresden 2006 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster: Films(1-36) Transp(37-56) Ex.Bias(57-67) Spindyn(68-80) Micromag(81-95) Particle(96-109) Imag.+Surface(110-113) Spinelectr(114-122) Theory+Micromag(123-131) Spinstr+Aniso(132-142) MagMat(143-156) Meas(157,158) MolMag+Kondo(159-162) Postdead(163-)

MA 20.58: Poster

Dienstag, 28. März 2006, 15:15–19:15, P1

Angular dependence of Magnetization Reversal In Exchange Biased Multilayers — •Amitesh Paul, Thomas Brueckel, Emmanuel Kentzinger, and Ulrich Ruecker — IFF-Forschungszentrum Jülich

Recently we observed sequential and symmetric magnetization reversal of the ferromagnet (FM) layers by domain wall motion for exchange coupled FM and antiferromagnetic (AF) multilayer systems such as [IrMn/CoFe]_10 [1] and [Co/CoO]_20. This symmetric reversal on both branches of the hysteresis loop without the usually observed magnetization component perpendicular to the applied field - follows the theoretical speculation of an alignment of the field-cooling axis (H_{FC}) with the applied field axis (H_a) by Beckmann et al [2]. In the present case, we investigate the same polycrystalline IrMn/CoFe sample measuring along each full magnetization loop: increasing (H_a along H_{FC}) and decreasing (H_a opposite H_{FC}), by specular and off-specular Polarized Neutron scattering as we vary the directions (theta) of the H_a with respect to the unidirectional anisotropy direction or the H_{FC} direction. Depending upon theta, the remagnetization behavior of all FM layers takes place sequentially which is either by nonuniform mode (via domain formation) or uniform mode (via coherent rotation) and also simultaneously which is by uniform mode only. [1] A. Paul et al., Phys. Rev. B 70, 224410 (2004). [2] B. Beckmann et al., Phys. Rev. Lett. 91, 187201 (2003).