The Inverted Cylindrical Magnetron Sputtering (ICMS) technique been used to fabricate YBCO step-edge dc SQUIDs. Steps are obtained by standard ion milling procedure on LaAlO3 (100) substrates using Nb-masks patterned by reactive ion etching. Thin films are then deposited under different conditions (both step and deposition angles) and patterned by standard lithography and wet chemical etching. An analysis of junction properties in terms of step height and film thickness has been carried out. Measurements on current vs magnetic field and SQUID voltage response measurements have been performed. Their temperature dependences have been also considered. Operating temperature as high as 77 K has been achieved. At 4.2 K the SQUIDs show a maximum voltage to flux transfer function (∂V/∂φ)max=870 μV/Φ0 and a good periodicity of the V-φ modulation up to 20 Φ0 without any sign of hysteresis.
Fabrication of YBCO step-edge Josephson junctions by inverted cylindrical magnetron sputtering technique
PAGANO, Sergio;
1995-01-01
Abstract
The Inverted Cylindrical Magnetron Sputtering (ICMS) technique been used to fabricate YBCO step-edge dc SQUIDs. Steps are obtained by standard ion milling procedure on LaAlO3 (100) substrates using Nb-masks patterned by reactive ion etching. Thin films are then deposited under different conditions (both step and deposition angles) and patterned by standard lithography and wet chemical etching. An analysis of junction properties in terms of step height and film thickness has been carried out. Measurements on current vs magnetic field and SQUID voltage response measurements have been performed. Their temperature dependences have been also considered. Operating temperature as high as 77 K has been achieved. At 4.2 K the SQUIDs show a maximum voltage to flux transfer function (∂V/∂φ)max=870 μV/Φ0 and a good periodicity of the V-φ modulation up to 20 Φ0 without any sign of hysteresis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
