Giant magnetoresistance effects in gel-like matrices

We present transport measurements with magnetoresistance effect amplitudes of up to 260% at room temperature obtained in granular systems consisting of Co nanoparticles embedded in conductive gels as a non-magnetic matrix. In order to gain a better understanding of the transport mechanism in gel during measurement, the granular system was simultaneously monitored by optical microscopy. Gel-like matrices with different conductivities and viscosities were tested and will allow us to realize a highly sensitive granular giant magnetoresistance sensor without the need for lithographic techniques.