Proposal for a spintronic femto-Tesla magnetic field sensor
  We propose a spintronic magnetic field sensor, fashioned out of quantum wires, which may be capable of detecting very weak magnetic fields with a sensitivity of ~ 1 femto-Tesla per root Hertz at a temperature of 4.2 K and ~ 80 femto-Tesla per root Hertz at room temperature. Such sensors have applications in magnetometry, quantum computing, solid state nuclear magnetic resonance, magneto-encephalography, mine detection, ground incursion detection and anti-submarine warfare. 
S. Bandyopadhyay and M. Cahay