Paper-based anisotropic magneto-resistive thin film sensor for educational applications

Více o knize

The reduction in sensor costs, particularly through low-cost materials, is essential for achieving a global trillion-sensor ecosystem. Recently, paper has emerged as a promising material for low-cost sensors. This work explores the design, fabrication, and characterization of a paper-based anisotropic magnetoresistive sensor using both empirical and computational approaches. The inherent properties of traditional paper—such as high surface roughness, porosity, and mechanical bendability—pose challenges for creating a consistently sensitive anisotropic magnetoresistive thin film sensor. Empirical findings indicate that the mechanical characteristics of paper significantly influence the magnetic quality of the permalloy thin film. As the thickness of the permalloy film increases, both the magnetic and electromagnetic properties of the paper-based permalloy improve. Additionally, the maximum pore size on the paper surface is crucial for determining production yield and the resolution limits of patterned paper-based permalloy thin films. A computational model indicates that the fibrous nature of the paper consistently shifts the angular anisotropy of the ferromagnetic coating by approximately 45°. Ultimately, a sensor achieving a maximum anisotropic magneto-resistive effect of 0.4% was developed with a permalloy thickness of 900 nm on a paper substrate exhibiting an average surface roughness of 2.04 µm.