The passage of swift heavy ions through dielectric layers (SiO2 or SiON) on silicon, creates ion tracks in them. After the etching and filling of these ion tracks with a suitable material, a novel electronic structure acronymed TEMPOS - 'Tunable Electronic Materials with Pores in Oxide on Silicon' has been realized. Several electronic devices, both, active and passive, have been fabricated and systematically studied in the last few years. Sensors have also been successfully made and characterized using the TEMPOS structure as it offers a high surface to volume ratio resulting in fast response time and high sensitivity of the sensor. In continuation with these studies, in the present paper, ferrofluids have been inserted in the ion tracks to study their behaviour in confined geometry and for subsequently obtaining magnetic sensors. A comparative study has been done between the aqueous and non-aqueous ferrofluids. Insertion of the ferrofluids in the ion tracks exhibits a change in the I-V behaviour in the presence of a magnetic field which can be exploited for obtaining the above said sensor. (C) 2010 Elsevier Inc. All rights reserved.