Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 49: POSTER II

MA 49.4: Poster

Donnerstag, 19. März 2015, 15:00–18:00, Poster A

Giant magnetoresistance effects in gel-like matrices: comparing theoretical and experimental data — •Thomas Rempel¹, Judith Meyer¹, Lisa Teich², Martin Gottschalk¹, Karsten Rott¹, Christian Schröder², and Andreas Hütten¹ — ¹Center for Spinelectronic Materials and Devices, Physics Department, Bielefeld University, PB 100131, D-33501 Bielefeld, Germany — ²Bielefeld Institute of Applied Materials Research, University of Applied Sciences Bielefeld, PB 101113, D-33511 Bielefeld, Germany

High GMR effects of up to 260% have been shown by Meyer et al. by dispersing carbon coated cobalt nanoparticles into non-magnetic, conductive, water-based gel matrices. While these gels tend to dry out and lack reproducibility due to low gel viscosity, gels with a liquid-solid transition such as agarose gel showed high and reproducible GMR effects of up to 60% over a long period of time. Therefore, they represent a promising candidate for future, low cost printable GMR sensor devices. To investigate the influence of magnetic coupling and particle superstructures on the magnetoresistance for agarose based gel systems, we compare transport measurements with theoretical calculations, which indicate a collective behavior of the nanoparticles due to dipole-dipole interactions. By the use of a dual beam system consisting of a focused ion beam and a scanning electron microscope, the particle arrangement for different particle superstructures has been explored. The information about the particle arrangement was used to perform stochastic spin dynamics simulations based on a point-dipole approach to compare the results with the experimental data.