# Dual-Layer Anomalous Hall Effect Sensor for Enhanced Accuracy and Range in Magnetic Field Detection

## TL;DR

This paper presents a new dual-layer magnetic sensor using NiCo2O4 that improves accuracy and range for magnetic field detection.

## Contribution

A novel dual-layer NiCo2O4-based sensor design with strain modulation to achieve enhanced sensitivity and wide measurement range.

## Key findings

- The sensor achieved 10,000 V/(AT) sensitivity within a ±0.1 mT range.
- An ultra-wide measurement range of ±1000 mT was realized by adjusting the top NiCo2O4 layer thickness.
- The dual-layer design enabled varied detection ranges and improved integration.

## Abstract

This study introduces a method aimed at enhancing both the accuracy and the range of magnetic field sensors, which are two critical parameters, in a novel NiCo2O4-based anomalous Hall effect sensor. To fine-tune the linear range of the sensor, we introduced epitaxial strain using a MgAl2O4 cover layer, which significantly influenced the strain-modulated magnetic anisotropy. A NiCo2O4/MgAl2O4/NiCo2O4/MgAl2O4 heterostructure was further constructed, achieving differentiation in the material characteristics across both upper and lower NiCo2O4 layers through the modulation of thickness and strain. A dual-layer Hall bar was designed to enhance the integration of the sensor, offering varied detection ranges. This approach enabled the realization of ultrahigh sensitivity, measuring 10,000 V/(AT) within a ±0.1 mT range, and a competitive sensitivity of 60 V/(AT) within a ±5 mT range. By reducing the thickness of the top NiCo2O4 layer, an ultra-wide measurement range of ±1000 mT was also achieved. These results highlight the considerable promise of NiCo2O4-based anomalous Hall effect devices as compact, multi-range tools in the domain of magnetic sensing technology.