Presentation Information
[EDP1-04]Developments of SQUID System for Detecting Spontaneous Magnetic Field in Microscopic Superconductors
*Mitsuhiro Teshigawara1, Makoto Ono1, Hirotake Yamamori2,3, Yasunori Mawatari2, Rikizo Yano1, Satoshi Kashiwaya1 (1. Nagoya Univ. (Japan), 2. AIST (Japan), 3. NAOJ (Japan))
Keywords:
SQUID,Broken Time-Reversal Symmetry,Spontaneous magnetic field,Unconventional Superconductor
[Purpose]
We report on the design and fabrication of the SQUID system optimized for detecting spontaneous magnetic fields due to broken time-reversal symmetry in unconventional superconductors, such as Sr2RuO4 and CaAgP.
[Method]
We designed a micro-scale SQUID loop to achieve enough magnetic coupling from a single domain of a few micrometers, while fixing the shielding parameter and McCumber parameter at reasonable values. We also developed a technique for integrating single crystals into the SQUID loop for achieving the optimum magnetic coupling.
[Results]
We first focused on NbSe2 to detect magnetic properties other than the spontaneous magnetic field. By using the FIB processing, we fabricated single crystals into small pieces of a few micrometers in size, and then integrated them directly into the SQUID loop.
[Consideration]
We measured the Ic modulation of the SQUID both before and after integrating the crystal. By comparing the period of the modulation, we succeeded in detecting the Meissner effect from a microscopic NbSe2 crystal.
[Conclusion]
We developed a SQUID system that is capable of detecting the magnetic properties of micro-scaled crystals. In the future, we will use this system to detect spontaneous magnetic fields induced by broken time-reversal symmetry superconductors.
We report on the design and fabrication of the SQUID system optimized for detecting spontaneous magnetic fields due to broken time-reversal symmetry in unconventional superconductors, such as Sr2RuO4 and CaAgP.
[Method]
We designed a micro-scale SQUID loop to achieve enough magnetic coupling from a single domain of a few micrometers, while fixing the shielding parameter and McCumber parameter at reasonable values. We also developed a technique for integrating single crystals into the SQUID loop for achieving the optimum magnetic coupling.
[Results]
We first focused on NbSe2 to detect magnetic properties other than the spontaneous magnetic field. By using the FIB processing, we fabricated single crystals into small pieces of a few micrometers in size, and then integrated them directly into the SQUID loop.
[Consideration]
We measured the Ic modulation of the SQUID both before and after integrating the crystal. By comparing the period of the modulation, we succeeded in detecting the Meissner effect from a microscopic NbSe2 crystal.
[Conclusion]
We developed a SQUID system that is capable of detecting the magnetic properties of micro-scaled crystals. In the future, we will use this system to detect spontaneous magnetic fields induced by broken time-reversal symmetry superconductors.