Fabrication and characterization of composite nanofiber GMR sensor for low magnetic field sensing

Abstract

Nanotechnology acts as a powerful tool for manipulating matter at the nanodimensional newlinescale. This feature enables scientists and instruments personnel to use in a newlinewide variety of instruments and formats for bio-sensing with very high speed, newlineefficiency, and sensitivity. One such property widely used in the development of sensors newlinefor various applications is the magnetic properties. Advanced sensor instrumentation newlinepaved the way to utilize the magnetic-based sensing mechanism called Giant newlineMagnetoresistive (GMR) technology to precisely and accurately detect and quantify the newlinebiological entities. Being a sensitive technique, it yields portable instruments for newlinesocietal applications at an affordable cost. Also, the GMR fabrication process is in line newlinewith the conventional thin-film fabrication technique, it allows for mass production of newlinethe instruments. newlineIn this work, Giant magnetoresistive sensors are being fabricated from newlineelectrospun composite nanofiber for detecting the stray magnetic field produced by the newlinemagnetic nanoparticle as well as by the nanoparticle tagged biomolecule under newlinemagnetic excitation. This dissertation will focus on the following five topics which newlineimply the application of magnetic nanotechnology for bio-sensing applications. First, newlinethe GMR sensor development method, starting from a thin- film based multi-layer newlinesystem, granular thin-film system, and composite nanofiber-based system. The working newlineprinciple of various methods and their theoretical background are elaborately being newlinediscussed. How the magnetic sensor can be used for detecting bio-entities can be newlinedescribed. Second, how the nanostructured material and its unique features are used in newlinethe fabrication of GMR biosensors. newline