title: Batch-fabrication of cantilevered magnets on attonewton-sensitivity mechanical oscillators for scanned-probe nanoscale magnetic resonance imaging.
abstract: We have batch-fabricated cantilevers with ∼100 nm diameter nickel nanorod tips and force sensitivities of a few attonewtons at 4.2 K. The magnetic nanorods were engineered to overhang the leading edge of the cantilever, and consequently the cantilevers experience what we believe is the lowest surface noise ever achieved in a scanned probe experiment. Cantilever magnetometry indicated that the tips were well magnetized, with a ≤ 20 nm dead layer; the composition of the dead layer was studied by electron microscopy and electron energy loss spectroscopy. In what we believe is the first demonstration of scanned probe detection of electron-spin resonance from a batch-fabricated tip, the cantilevers were used to observe electron-spin resonance from nitroxide spin labels in a film via force-gradient-induced shifts in cantilever resonance frequency. The magnetic field dependence of the magnetic resonance signal suggests a nonuniform tip magnetization at an applied field near 0.6 T.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA.
authors.forename: Steven A
authors.initials: SA
authors.lastname: Hickman
authors.forename: Eric W
authors.initials: EW
authors.lastname: Moore
authors.forename: SangGap
authors.initials: S
authors.lastname: Lee
authors.forename: Jonilyn G
authors.initials: JG
authors.lastname: Longenecker
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Wright
authors.forename: Lee E
authors.initials: LE
authors.lastname: Harrell
authors.forename: John A
authors.initials: JA
authors.lastname: Marohn
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D005240:Feasibility Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008280:Magnetics; D055595:Mechanical Phenomena; D008854:Microscopy, Electron; D036103:Nanotechnology / Q000379:methods*; D009532:Nickel / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D046590:Spectroscopy, Electron Energy-Loss
chemical_list: D009532:Nickel; D012825:Silicon