Yba_2Cu_3O_(7-#delta) dc SQUID array for multichannel magnetometry and multichannel flip-chip current sensors

摘要

We have prepared arrays of single-layerwasher-type dc superconducting quantum interferencedevices (SQUIDs) on 10 mm x 10 mm bicrystalsubstrates. Each SQUID in the array is equipped withits own modulation loop, which makes a separateoperation of them possible. Arrays containing nine or11 dc SQUIDs have been tested and the crosstalkbetween neighbouring channels has been found to be5percent. The field sensitivity of the SQUIDs is 85 nT#PHI#_0~-1 and 105 nT #PHI#_0~-1 for the nine- and11-device array, respectively. The equivalent flux noiseis typically <#mu#20 #PHI#_0 Hz-1/2 down to 1 Hzwith ac bias reversal. A field resolution of less than 2.1pT Hz~-1/2 has been obtained for at least eightchannels on a chip. By using multiturnYba_2Cu_3O_(7-#delta#) input coils and mountingthem in a flip-chip configuration together with thesingle-layer de SQUIDs we have been able to buildthree-channel current sensors. The current sensitivityequals 3-3.5 #mu#A #PHI#_0~-1 depending on thealignment of the flip-chip configuration. The currentresolution of the devices is <70 pA Hz~-1/2. We showthe possibility of building sensitive magnetometers byconnecting the input coil of these current sensors to anormal-conducting pickup antenna.