Current trends in planar Hall effect sensors: evolution, optimization, and applications

The benefits conferred by the thermal stability, very low detection limit, and high sensitivity of planar Hall effect (PHE) sensors have supported up-to-date diversity of applications like nT magnetometer, current sensing, or low magnetic moments detection in lab-on-a-chip devices. Herein, we demonstrate in this review the implications linked to planar Hall effect sensors, initiating from the backbone of PHE and its evolution throughout the recent few decades. Key parameters affecting sensors' performance such as noise different sources, thermal stability, and magnetoresistance magnitude are discussed. The progression of sensor junction from disk, cross to bridge, ring, and ellipse configuration is delivered. Moreover, the logical sequence of structure from a single magnetoresistive layer to bi-, trilayers, and spin-valves is briefly investigated. Research contributions to the development of these sensors are highlighted with the focus on microfluidics and flexible sensorics areas. The conclusions extracted from this review are beneficial for the production, development, and performance quality validation of planar Hall effect-based devices and microfluidics and future expectations. Not at least, this review can be a valuable source of information for scientists that intend to use PHE for fundamental research or to develop new applications and devices.