Abstract
Magnetic sensing elements have been used extensively in industrial equipments, so the research for the electrical characteristics of sensing elements and the optimization of its parameters has become more and more important. Based on the technique of micro electro mechanical systems (MEMS) and giant magnetoresistance (GMR) effect, a bridge-type GMR sensing element had been designed and produced. This element is combined with a linear guideway and a magnetic encoder, and precise displacement control can be performed by integrating it with outside electric circuits. Optimization of parameters had studied by changing the layer thickness of structure, different shapes of magnetic films and multilayer effect for the improvement of the magnetoresistance ratio. The experimental results show that the magnetoresistance ratio and the linear application section are shrinked by changing the thickness of free layer. The different edge shapes of magnetic films changes the output signal of the system, shapes such as metal wire end, circular end, elliptic end, and chained ball type can cause the output signal fixed. The effect of multilayer increases magnetoresistance ratio, but does not obvious due to the shunting effect.