Integrated YBa/sub 2/Cu/sub 3/O/sub 7/ multi-loop magnetometers at 77 K

Abstract

We present a multi-loop DC SQUID magnetometer operated at 77 K. In a multi-layer process YBa/sub 2/Cu/sub 3/O/sub 7/, PrBa/sub 2/Cu/sub 3/O/sub 7/, and SrTiO/sub 3/ films are deposited by KrF-excimer laser deposition on SrTiO/sub 3/(100) substrates. The preparation consists of four film deposition and three patterning steps. We employ YBa/sub 2/Cu/sub 3/O/sub 7/ Josephson junctions with artificial barriers of PrBa/sub 2/Cu/sub 3/O/sub 7/ in a ramp-type geometry. The characterization is made by electrical transport and by noise measurements. The measured magnetic field sensitivity of 1.25 nT//spl Phi//sub 0/ of our device fits well with the calculated value of 1.17 nT//spl Phi//sub 0/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>