Development of a Two-Dimensional Micro-SQUID Array for Investigation of Magnetization Spatial Distribution

Abstract

We developed a two-dimensional array of superconducting quantum interference devices (SQUIDs) for investigation of fine spatial distribution of magnetization in superconducting Sr 2 RuO 4 . Micrometer-sized SQUIDs based on homogeneously formed Al/AlO x /Al tunnel-type Josephson junctions were fabricated using shadow evaporation technique. Unnecessary electrodes formed by the shadow evaporation were removed by inductively coupled plasma reactive ion etching, in order to realize a dense array of SQUIDs. We measured the magnetic modulation of the maximum Josephson current of each SQUID in the array and evaluated the interaction among the SQUIDs.