Application of GMR line sensor to detect the magnetic flux distribution for nondestructive testing

Abstract

We have developed a GMR line sensor which can arrange many GMR elements in a line on a polyimide film. This GMR line sensor detects the magnetic field distribution in a plane by only a single scan. We use the multilayer GMR element. This element can detect a magnetic field impress from directions of an element length and an element width. And the GMR line sensor has omnidirectional magnetic sensitivity. We applied this sensor to a nondestructive magnetic leakage flux testing. The output of this sensor does not depend on the direction of leakage flux, therefore, this sensor can detect any direction of defect. Using the GMR line sensor, the shape of the defect will be identified by a single scan.