Nanomechanical Resonators for Cryogenic Research

Suspended aluminum nanoelectromechanical resonators have been fabricated, and the manufacturing process is described in this work. Device motion is driven and detected with a magnetomotive method. The resonance response has been measured at 4.2 K temperature in vacuum and low-pressure ⁴He gas. At low oscillation amplitudes, the resonance response is linear, producing Lorentzian line shapes, and Q values up to 4400 have been achieved. At higher oscillation amplitudes, the devices show nonlinear Duffing-like behavior. The devices are found to be extremely sensitive to pressure in ⁴He gas. Such device is a promising tool for studying properties of superfluid helium.