3D SQUID microscope for sensing vector magnetic fields

2015 Fiscal Year Final Research Report

• Project/Area Number: 15K13979
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Electron device/Electronic equipment
• Research Institution: Osaka Prefecture University
• Principal Investigator: Ishida Takekazu 大阪府立大学, 工学(系)研究科(研究院), 教授 (00159732)
• Co-Investigator(Kenkyū-buntansha): MAEZAWA Masaaki 国立研究開発法人産業技術総合研究所, ナノエレクトロニクス研究部門, 主任研究員 (40357976) ; HAYASHI Masahiko 秋田大学, 教育文化学部, 教授 (60301040)
• Co-Investigator(Renkei-kenkyūsha): HIDAKA Mutsuo 国立研究開発法人産業技術総合研究所, ナノエレクトロニクス研究部門, 上級主任研究員 (20500672) ; MIYAJIMA Shigeyuki 大阪府立大学, 客員研究員 (50708055)
• Project Period (FY): 2015-04-01 – 2016-03-31
• Keywords: 超伝導材料・素子 / SQUID素子 / 走査型顕微鏡 / 画像処理

Outline of Final Research Achievements

We designed a vector sensor for sensing magnetic fields by using a 3-dimensional (3D) scanning superconducting quantum interference device (SQUID) microscope. A vector senor consists of three SQUID sensors on the same chip and each SQUID sensor has a pick-up coil for X, Y, or Z direction. Three coils with readout circuits are configured in orthogonal with each other to measure the magnetic field vector. The critical current density Jc of a Josephson junction (JJ) is 320 A/cm2 and the minimum critical current Ic of JJ becomes 12uA. We use an XYZ piezo-driven scanner for controlling the position of the pick-up coils in the range of 5 mm x 5 mm at low temperatures. The room-temperature electronics has the bandwidth of 6 MHz.
The software for the image processing of the scanning SQUID microscope has been improved so that the estimated magnetic flux after process is close to the true value. A function to calculate the magnetic flux inside an area on the image has been newly provided.

Free Research Field

総合理工