Improvement of the detectivity in an Fe–Sn magnetic-field sensor with a large current injection. (1st May 2022)

• Record Type: Journal Article
• Authors: Shiogai, Junichi; Jin, Zhenhu; Satake, Yosuke; Fujiwara, Kohei; Tsukazaki, Atsushi
• Is Part Of: Japanese journal of applied physics. Volume 61:Number SC(2022)
• Publication Date: 2022-05-01
• Subjects: magnetic-field sensor -- anomalous Hall effect -- Fe–Sn thin film device -- Noise spectral density; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/ac465a
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: A ferromagnetic nanocrystalline Fe–Sn is an excellent platform for magnetic-field sensor based on anomalous Hall effect (AHE) owing to simple fabrication and superior thermal stability. For improvement of the magnetic-field sensitivity, doping impurity and increasing injection current are effective approaches. However, in the light of magnetic-field detectivity, the large current may increase the voltage noise. In this study, a maximum allowable current was improved by employing the overlayer electrode configuration on a Ta-doped Fe–Sn AHE sensor. In noise measurements, the 1/ f noise becomes significant with increasing the current at low frequency, resulting in saturation of the detectivity to 240 nTHz −1/2 at 120 Hz. At high frequency, the detectivity reaches 48 nTHz −1/2 at 3.1 mA showing ten times improvement of the detectivity compared with the non-doped Fe–Sn AHE sensor. Material design and device structure optimization will accelerate further improvement of the sensing properties of the Fe–Sn-based AHE sensor.