Coupled NanoSQUIDs and Nano-Electromechanical Systems (NEMS) Resonators

Recent developments in cryogenic nano-electromechanical (NEMS) resonators have shown that they can address some fundamental physics, for example in achieving the ground state of a mechanical resonator and entanglement with an electromagnetic resonator. In contrast, little work has been reported on using what is arguably the most sensitive measuring device, a SQUID, to directly interact with, and thus interrogate, a NEMS resonator. We report here our initial experimental results aimed towards forming an optimized coupled micro/nano-mechanical resonator and a focused ion beam patterned Nb SQUID, possessing exceptionally low noise (~200nΦ_0/Hz^1/2 above 1 kHz), and operating above 4.2 K. We describe our first results from a paddle-shaped mechanical resonator with a diameter of 15 μm coupled to a Nb SQUID loop. Finally, we describe the construction of our first true nanoscale-coupled, double-clamped cantilever and nanoSQUID (rectangular loop area 100 nm × 900 nm).