Ultrasensitive anomalous Hall effect in SiO2/Fe-Pt/SiO2 sandwich structure films

Abstract

Ultrasensitive anomalous Hall effect has been demonstrated in a SiO 2 /Fe-Pt/SiO 2 sandwich structure. Owing to the interfacial electron scattering, the Hall resistivity is appreciably enhanced for the thin Fe-Pt layers of high quality; meanwhile, a large interfacial anisotropy is formed and further enhanced through annealing, leading to a room temperature Hall slope up to 2160 lX cm/T and field sensitivity of 12 000 X/T at Fe-Pt thickness $1.8 nm. This number is an order magnitude higher than the best semiconductor sensitivity. Other important technical characteristics, such as electrical resistivity and temperature coefficient, are also suitable to practical magnetic Hall sensor development.

Unconventional scaling of the anomalous Hall effect accompanying electron localization correction in the dirty regime

“…The equiatomic FePt alloy layers formed a homogenously continuous structure, which was confirmed by transmission electron microscopy observations. 21 The x-ray diffraction pattern revealed the face-centered cubic polycrystalline structure of the FePt films (chemically disordered). Transport measurements were carried out on a Quantum Design PPMS-14H at 300-2 K. In studying Hall effect, the offset signal was removed, and ρ AH was obtained as the zero field extrapolation of the high field ρ xy (H ).…”

Ultrahigh Sensitivity of Anomalous Hall Effect Sensor Based on Cr-Doped Bi2Te3Topological Insulator Thin Films

“…Ultrahigh AHE sensitivity has been reported in various metallic heterostructure and metal-oxide interfaces [4][5][6]. Already achieved sensitivity of the AHE-based devices exceeds 1000 Ω/T, which surpasses the sensitivity of semiconducting Hall sensors [4]. It is believed that the AHE is an alternative approach to largely increase the Hall sensitivity and response frequency while keeping the low power consumption.…”

“…Besides using Lorenz force causing charge accumulation to achieve Hall in semiconductor, there is a emergent developing field known as spin-dependent HE including quantum Hall effect (QHE), anomalous Hall effect (AHE) and spin Hall effect (SHE) [3]. Ultrahigh AHE sensitivity has been reported in various metallic heterostructure and metal-oxide interfaces [4][5][6]. Already achieved sensitivity of the AHE-based devices exceeds 1000 Ω/T, which surpasses the sensitivity of semiconducting Hall sensors [4].…”

MegaOhm extraordinary Hall effect in oxidized CoFeB

“…As mentioned above, high EHE sensitivity of order 10 4 Ω/T reported in Refs. [6,7] was achieved in ultrathin films with of few µcm by reducing the saturation field to 10 -3 T. Our samples have no out-of-plane anisotropy, saturation field remains high (about 1.5 T), and high sensitivity is achieved due to very large EHE resistivity . with 0 increasing from 1 K for sample 1 with room temperature resistivity 10 -2 cm to 25 K for sample 3 with resistivity 3.2 cm.…”

“…Remarkably high magnetic field sensitivity beyond 10 4 /T, which is larger than the best Hall effect sensitivity ever found in semiconducting materials [5], was recently reported [6,7]. The strategy adapted to achieve such sensitivity was by using very thin ferromagnetic films with enhanced spinorbit surface scattering and tailored perpendicular magnetic anisotropy that enabled easy out-of-plane rotation of magnetization with low saturation field [8].…”