Eur. Phys. J. B (2013) 86: 51
https://doi.org/10.1140/epjb/e2012-30657-1

Regular Article

Optimization of the coupling between piezoresistivity and magnetoelasticity in an elastomagnetic composite to sense a spatial gradient of the magnetic field^*

¹ CNR-SPIN, Department of Physical Sciences, Federico II University of Naples, p.le V.Tecchio 80, 80125 Naples, Italy
² Department of Chemical Engineering, Federico II University of Naples, p.le V. Tecchio 80, 80125 Naples, Italy

^a e-mail: ausanio@na.infn.it

Received: 21 July 2012
Received in final form: 20 November 2012
Published online: 13 February 2013

Abstract

Elastomagnetic samples made of quasi-ellipsoidal nickel microparticles separated by a thin silicone layer were produced. A static magnetic field was applied during the process of sample solidification, obtaining a preferred orientation of the particles major axis through the coupling of the magnetic moment with the easy magnetization axis. The influence of the particle pre-orientation on the elasticity, piezoresistivity and magneto-piezoresistivity were investigated and discussed in order to maximize the resistance change due to a moderate magnetic field gradient, in view of conceiving an innovative core material for sensor devices. It was shown as the relative change of resistance induced by a low magnetic field gradient can be improved of over 15% in comparison with previous results, approaching an absolute value of the magneto-piezoresistive ratio equal to 80%. Since a local magnetic field change can be also produced by a displacement of a magnetic body, in perspective the effect can be applied for sensing position or mechanical vibration too.