Abstract
We have fabricated high-Tc dc superconducting quantum interference devices (SQUIDs), which have different geometries of the hole and configurations of current injection leads, in the direct-coupling magnetometer, and measured the coupling efficiency of the flux generated by the injected current. It has been found that the coupling is efficient in the case where the current flows uniformly across the width of the path around the SQUID hole. High coupling of more than 80% was obtained in a geometry of narrow parallel strips with wide slit of the SQUID hole between them.