Search

We developed a transverse second-order SQUID gradiometer from a single layer of high T[sub c] film, which can measure the off-diagonal element d²B[sub z]/dxdy of the second-order field gradient. In this design, four-way 'clover-leaf' pick-up loops are coupled directly to a 4-junction dc SQUID in such a way that the coupling polarity of the two diagonal loops is opposite to that of the other two loops. The pickup loops are intrinsically balanced for both uniform field and the 1st-order gradient. We made the device by using a pulsed-laser deposition and Ar ion-milling with photolithography. The entire structure was made on a single crystalline SrTiO[sub 3] substrate. The gradiometer responded sensitively to the 2nd-order gradient. Induced field focused on the SQUID loop by the screening current flowing along the device perimeter is believed the major off-balancing factor, which can be balanced by adding a closed superconducting loop just outside the device perimeter or merging facing sides of neighboring loops. [ABSTRACT FROM AUTHOR]

Investigates the effects of annealing step-edges on single-crystal substrates on YBa[sub 2]Cu[sub 3]O[sub 7] Josephson junctions. Fabrication of the step-edge by argon-ion milling technique; Characterization on the effect of annealing by atomic force microscope and current-voltage (I-V); Assessment on the surface of the substrates and I-V characteristics.

Describes a prototype single-layer second-order high temperature superconducting quantum interference device (SQUID) magnetometer designed for detection of transverse field gradient. SQUID design and fabrication; Measurement of device response to field gradients along the transverse direction; Enhancement of the inductance of pickup loops.

Focuses on the design and fabrication of second-order direct current superconducting quantum interference device gradiometer based on high temperature superconducting film. Film formation by photolithography and ion milling; Current-voltage characteristics; Voltage modulation curves.

Discusses the effects of step conditions on the properties of yttrium barium copper oxide step-edge Josephson junctions. Current-voltage characteristics; Critical current modulation; Ion milling and pulsed laser deposition.

Discusses the effects of capacitative shunt on the current-voltage characteristics of high temperature Josephson junctions. Effect of temperature on critical current and normal state resistance; McCumber junction parameter.