| AVS 56th International Symposium & Exhibition | |
| Graphene Topical Conference | Wednesday Sessions |
| Session GR+MI-WeM |
| Session: | Spins in Graphene: Injection and Manipulation |
| Presenter: | S. Pisana, Hitachi GST |
| Authors: | S. Pisana, Hitachi GST P.M. Braganca, Hitachi GST M. Pelliccione, Stanford University M. Nishioka, Hitachi GST N. Smith, Hitachi GST E.E. Marinero, Hitachi GST B.A. Gurney, Hitachi GST |
| Correspondent: | Click to Email |
Extraordinary magnetoresistance (EMR) has recently attracted interest for magnetic field sensing applications in the magnetic storage industry [1]. The effect is particularly attractive given the magnitude of its response, which is comparable to current giant magnetoresistive sensors for mesoscopic device sizes, and its lack of thermal magnetic noise, as the structure does not incorporate ferromagnetic materials. EMR devices consist of hybrid semiconductor-metal structures in which the exclusion of current from a metal shunt in a magnetic field modulates the resistance of the device. This functionality can be advantageously combined with the Hall effect with appropriate variations in the device’s lead configuration [2].
The EMR response is proportional to the semiconductor’s mobility, among other factors. Furthermore, the successful implementation of this type of device for future read sensors in magnetic storage applications restricts the sensing element’s position within a few nanometers from the source of magnetic field.
Graphene, a single atom-thick layer of graphite, is a promising electronic material, given its high mobility, high current carrying capabilities and linearly dispersive electronic bands [3]. These qualities make it a promising candidate for magnetic field sensing in an EMR device, allowing for the conceptually smallest magnetic spacing in a structure that is free from thermal magnetic noise.
In this work, we outline the first implementation of graphene EMR devices. We will discuss their mesoscopic fabrication and demonstrate response that is comparable to current magnetic field sensors. Devices with minimum feature of 150 nm (Figure 1) show signals above 2 mV in magnetic fields of 350 Oe at room temperature. The results are summarized in the context of future magnetic field sensors for terabit density data storage.
[1] Solin, S. A.; Thio, T.; Hines, D. R. & Heremans, J. J.; Science 289, 1530 (2000)
[2] Boone, T. D.; Smith, N.; Folks, L.; Katine, J. A.; Marinero, E. E. & Gurney, B. A.; IEEE Electron Device Letters 30, 117 (2009)
[3] Geim, A. K. & Novoselov, K. S.; Nature Materials 6, 183 (2007)