Micron-Scale Anomalous Hall Sensors Based on FexPt1−x Thin Films with a Large Hall Angle and near the Spin-Reorientation Transition

Abstract

In this work, we fabricate and characterize an energy-efficient anomalous Hall sensor based on soft-magnetic FexPt1−x thin films with a large anomalous Hall angle. By varying the composition of the FexPt1−x alloy, its layer thickness and interfacial materials, the magnetization is tuned to be near the spin transition between the perpendicular and in-plane reorientations. We performed magneto-transport and noise characterizations on anomalous Hall sensors with a small sensing area of 20 × 20 µm2 in the 180 to 350 K temperature range. We found the best performance in a 1.25-nm-thick Fe0.48Pt0.52 sandwiched by two 1.6-nm-thick MgO layers at room temperature. The sensor has a large anomalous Hall angle of 1.95%. Moreover, it has the best field detectability of 237.5 nT/√Hz at 1 Hz and 15.3 nT/√Hz at 10 kHz, as well as a high dynamic reserve of 112.0 dB. These results suggest that the FexPt1−x alloy system is suitable for energy-efficient anomalous Hall sensors, particularly in micro-sensing applications.

Interfacial Modulation on Co0.2Fe2.8O4 Epitaxial Thin Films for Anomalous Hall Sensor Applications

“…In our report, AHE signal sensitivity of CoFeO/G/MAO samples in the range of ±5 kOe is 0.0282Ω/kOe. Although there is still a gap compared with the sensitivity of reported anomalous Hall sensors based on metal alloy materials, ,, a method for realizing linear anomalous Hall signals based on oxide systems with a high Curie temperature (>790 K) , and chemical stability is proposed in our report for the first time. It has certain promoting significance for the future research of new oxide-based anomalous Hall sensors.…”

“…Most of the existing studies modulate the magnetic anisotropy of metal multilayers for better linearity and sensitivity. 5,6 Half-metallic spinel ferrite thin films have attracted wide attention in modern spintronics due to their stability and ease of fabrication. 7 Increasing interests are put into spinel ferrite thin films like Fe 3 O 4 , 7 CoFe 2 O 4 , 8 CuFe 2 O 4 , 9 and LiFe 5 O 8 .…”

“…However, the magnetization does not vary linearly with magnetic field strength. Most of the existing studies modulate the magnetic anisotropy of metal multilayers for better linearity and sensitivity. , …”

Giant magnetoresistance, Fermi surface topology, Shoenberg effect and vanishing quantum oscillations in type-II Dirac semimetal candidates MoSi$_2$ and WSi$_2$

“…[22] The existence of tilted Dirac cones can lead to some unique physical properties like Klein tunneling [23] and anomalous Hall effect, [24] which can be utilized in novel ultrasensitive magnetic sensors and memories. [25,26] However, there are many challenges and critical issues in growing single-crystalline MA 3 by deposition techniques due to high vapor pressure of Al, Ga and In. [27] In contrast, it has been shown that thin films of MoSi 2 can be easily prepared on different substrates, [11,12] thus providing an ideal platform for both basic and applied research.…”

Strain driven phase transition and mechanism for Fe/Ir(111) films

“…Iron and iron-based alloys are the most important materials used in magnetic devices, such as magnetic tunnel junction 26 – 28 , magnetic random access memory 29 , 30 and magnetic sensors 31 – 33 . Because of their different lattice structures, Fe/Ir interfaces function as a platform for controlling pseudomorphic growth, nanostructure evolution, and the formation of strained clusters.…”