Room‐Temperature Colossal Magnetoresistance in Terraced Single‐Layer Graphene

Abstract

Disorder‐induced magnetoresistance (MR) effect is quadratic at low perpendicular magnetic fields and linear at high fields. This effect is technologically appealing, especially in 2D materials such as graphene, since it offers potential applications in magnetic sensors with nanoscale spatial resolution. However, it is a great challenge to realize a graphene magnetic sensor based on this effect because of the difficulty in controlling the spatial distribution of disorder and enhancing the MR sensitivity in the single‐layer regime. Here, a room‐temperature colossal MR of up to 5000% at 9 T is reported in terraced single‐layer graphene. By laminating single‐layer graphene on a terraced substrate, such as TiO2‐terminated SrTiO3, a universal one order of magnitude enhancement in the MR compared to conventional single‐layer graphene devices is demonstrated. Strikingly, a colossal MR of >1000% is also achieved in the terraced graphene even at a high carrier density of ≈1012 cm−2. Systematic studies of the MR of single‐layer graphene on various oxide‐ and non‐oxide‐based terraced surfaces demonstrate that the terraced structure is the dominant factor driving the MR enhancement. The results open a new route for tailoring the physical property of 2D materials by engineering the strain through a terraced substrate.

Magnetic‐Sensitive Crack Sensor with Ultrahigh Sensitivity at Room Temperature by Depositing Graphene Nanosheets upon a Flexible Magnetic Film

“…It should be noticed that the magnetic sensitivity of M‐CS was attributed to crack effect, which is different form the conventionally physical magnetoresistance effect. [ 46 ]…”

Current Progress of Magnetoresistance Sensors

“…The discovery of graphene provided a powerful tool for developing MR materials as graphene possesses unique physical and chemical properties [84][85][86][87]. Large MR has been observed on MR systems based on monolayer graphene, bilayer graphene, and multilayer graphene (Figure 7) at room temperature or extremely low temperatures (1.9 K) [85,[88][89][90][91][92]. The results indicate the feasibility to design MR sensors with layered graphene systems, although specific substrates/preparation techniques are required in most circumstances.…”

“…The discovery of graphene provided a powerful tool for developing MR materials as graphene possesses unique physical and chemical properties [84][85][86][87]. Large MR has been observed on MR systems based on monolayer graphene, bilayer graphene, and multilayer graphene (Figure 7) at room temperature or extremely low temperatures (1.9 K) [85,[88][89][90][91][92].…”

2D Material Based Synaptic Devices for Neuromorphic Computing

“…[ 91 ] By laminating monolayer graphene on a terraced substrate, a room‐temperature colossal MR of up to 5000% at 9 T is reported. [ 114 ] Meanwhile, the tensile elastic strain has been proved to accelerate the hydrogen evolution reaction (HER) kinetics of sulfur vacancies in MoS 2 . [ 89–90 ]…”