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Graphene Hall-effect sensors for nanoscale magnetic field detection




Duration: 6 months full-time internship

Latest starting date: 04/03/2024

Localisation: LPCNO, INSA Toulouse
135 avenue de Rangueil
31077 Toulouse

Benjamin LASSAGNE, PhD
Thomas BLON, PhD

This research master's degree project could be followed by a PhD

Work package:
The Nanomagnetism group at LPCNO specializes in the study of the galvanomagnetic properties of graphene, with the ultimate aim of fabricating ultra-sensitive Hall-effect magnetic sensors based on boron nitride/graphene/boron nitride(hBN) heterostructures. The team has recently developed a comprehensive and novel model for the detailed understanding of the operation of graphene Hall-effect sensors, which has enabled it to significantly improve their performance (Figure) [1]. The group now focuses on using these graphene Hall-effect sensors to measure the static and dynamic magnetic properties of nanometer-sized ferromagnetic (FM) systems. The first area concerns the measurement, particularly at cryogenic temperatures, of highly promising 2D van der Waals FM materials such as CrI3, CrBr3, Cr2Ge2Te6 or FexGeTey [2], with the perspective of producing graphene/2D FM material spin heterostructures [3]. The second axis concerns the detection of high-frequency magnetic excitations in ferromagnetic dots and spin-wave propagation lines. Proof-of-concept of such detection could lift the technological bottleneck on nanoscale spin-wave detection and pave the way for magnonic devices [4].

(a) hBN/graphene/hBN Hall sensor fabricated at LPCNO. (b) and (c) Experimental resistance R and magnetic field sensitivity S of the graphene Hall sensor at room temperature under 100 mT and for two values of the bias current. (d) and (e) Corresponding simulated R and S using the developed model. From [7].

[1] L. Petit et al., NanoExpress, under review (2023) [2] C. Gong et al, Nature, 546, 265 (2017) [3] T. Song et al, Science 360, 1214 (2018) [4] A. Chumak et al, Nat Com. 5, 4700 (2014)

Areas of expertise:
Graphene, magnetic field sensors, Hall effect, 2D materials, van der Waals heterostructures

Required skills for the internship:
Background in condensed matter physics and nanophysics, aptitude for experimental studies.