Villari effect in silicone/FeGa composites

Abstract

This paper presents the results of the Villari effect study in FeGa magnetorheological composites with very low stresses. The composites consist of a silicone matrix and Fe75Ga25 powder of size ranging from 50 to 100 μ m. Two types of composites, one is with 45 wt% and the other one with 30 wt% of Fe75Ga25 powder have been manufactured. The Villari effect has been measured in both samples as-manufactured and in those in which a 1 T magnetic field has been applied after curing. The results indicate that the composites with an applied field of 1 T after curing show the greatest Villari signal even without any applied magnetic field. This fact allows a design of a low-cost force sensor and high performance. A simple model, based on the change in the cross-section of the composite, has been developed to explain the results obtained.