title: Tunable nanoscale graphene magnetometers.
abstract: The detection of magnetic fields with nanoscale resolution is a fundamental challenge for scanning probe magnetometry, biosensing, and magnetic storage. Current technologies based on giant magnetoresistance and tunneling magnetoresistance are limited at small sizes by thermal magnetic noise and spin-torque instability. These limitations do not affect Hall sensors consisting of high mobility semiconductors or metal thin films, but the loss of magnetic flux throughout the sensor's thickness greatly limits spatial resolution and sensitivity. Here we demonstrate graphene extraordinary magnetoresistance devices that combine the Hall effect and enhanced geometric magnetoresistance, yielding sensitivities rivaling that of state of the art sensors but do so with subnanometer sense layer thickness at the sensor surface. Back-gating provides the ability to control sensor characteristics, which can mitigate both inherent variations in material properties and fabrication-induced device-to-device variability that is unavoidable at the nanoscale.
authors.affiliation: San Jose Research Center, Hitachi Global Storage Technologies, 3403 Yerba Buena Road, San Jose, California 95135, USA.
authors.forename: Simone
authors.initials: S
authors.lastname: Pisana
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Braganca
authors.forename: Ernesto E
authors.initials: EE
authors.lastname: Marinero
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Gurney
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002244:Carbon / Q000737:chemistry*; D004581:Electronics; D004867:Equipment Design; D008280:Magnetics / Q000295:instrumentation*; D008420:Manufactured Materials; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D049329:Nanostructures; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D011312:Pressure; D012666:Semiconductors; D013696:Temperature; D014159:Transducers
chemical_list: D002244:Carbon