Synthesis and performance of polymer based magnetic composite sensing element

The commercial multi-mode optical fiber was coated with magnetic composite material prepared using Nd-Fe-B permanent magnet powder dispersed in poly (ethylene-co-vinyl acetate)-EVA. Characterization of microstructure, thermal stability and mechanical properties of the composite coatings with different Nd-Fe-B powder content were performed using Scanning Electron Microscope (SEM), Differential Scanning Calorimetry (DSC), and standard tensile tester, respectively. Experimental results show that composites with higher content of Nd-Fe-B powder have improved thermal and mechanical properties. Propagation characteristics of the constructed optical fiber magnetic sensing element (OFMSE) in the external magnetic field were investigated in relation to quality and composition of the applied composite coatings. The attenuation of optical signal with applied external magnetic field intensity was monitored and the results suggest that the sample with 50 wt-% of Nd-Fe-B provides the greatest sensitivity of the sensor element.