We report results about an optimized three-dimensional nanoSQUID based on niobium tunnel nanojunctions having the loop suspended to reduce the parasitic capacitance. The SQUID loop has a size of 400 x 600 nm(2) while the dimension of the square tunnel nanojunctions is 150 x 150 nm(2) with a density of the critical current of about 35 x 103 A/cm(2). The nanodevice has been characterized at liquid helium temperature; it has shown nonhysteretic current-voltage characteristics and smooth voltage-magnetic flux characteristics resulting in a very stable operation in a wide range of bias points. The spectral density of the magnetic flux noise in the white region, measured with a two-stage noise measurement setup, was as low as 300n Phi(0)/Hz(1/2) corresponding to a spin sensitivity of few Bohr magnetons for bandwidth unit.
Performance Optimization of a Three-Dimensional NanoSQUID Based on Niobium Tunnel Nanojunctions / Fretto, M.; Schmelz, M.; Vettoliere, A.; Zakosarenko, V.; De Leo, N.; Stolz, R.; Granata, C.. - In: IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY. - ISSN 1051-8223. - 28:7(2018). [10.1109/TASC.2018.2841906]
Performance Optimization of a Three-Dimensional NanoSQUID Based on Niobium Tunnel Nanojunctions
Fretto M.;De Leo N.;
2018
Abstract
We report results about an optimized three-dimensional nanoSQUID based on niobium tunnel nanojunctions having the loop suspended to reduce the parasitic capacitance. The SQUID loop has a size of 400 x 600 nm(2) while the dimension of the square tunnel nanojunctions is 150 x 150 nm(2) with a density of the critical current of about 35 x 103 A/cm(2). The nanodevice has been characterized at liquid helium temperature; it has shown nonhysteretic current-voltage characteristics and smooth voltage-magnetic flux characteristics resulting in a very stable operation in a wide range of bias points. The spectral density of the magnetic flux noise in the white region, measured with a two-stage noise measurement setup, was as low as 300n Phi(0)/Hz(1/2) corresponding to a spin sensitivity of few Bohr magnetons for bandwidth unit.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
