Ultra-sensitive Detection of Magnetic Nanoparticles by Giant Magnetoimpedance Effect

A revision of the giant magnetoimpedance (GMI)-based ultra-sensitive detectors of magnetic nanoparticles is addressed. Initially, the general structure and the factors that determine the performance of the ultra-sensitive detector are introduced. Then, the principles behind the GMI effect and the most common materials and geometries used in the sensor development are presented. Based on the previous framework, a brief discussion of the interaction established between the magnetic response of the magnetic nanoparticles (stray field) and the GMI sensing elements is carried out. A perspective on the optimization process of the GMI sensing elements toward the ultra-sensitive detection is provided. For this, a progressive outline from the pioneering works to some of the most sensitive reported detectors is provided. Finally, some new strategies to enhance the detection capacity of the proposed devices are pointed out.