Berlin 2015 – scientific programme
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MA: Fachverband Magnetismus
MA 49: POSTER II
MA 49.4: Poster
Thursday, March 19, 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.