High-field ESR using SQUID magnetometer

Abstract

We have developed high-field ESR system using commercially available SQUID magnetometer equipped with the superconducting magnet up to 5 T. This is a longitudinal magnetization detection type ESR. The minimum detectable spin number is evaluated as 2×1013 spins/G for 105 GHz. The most advantageous points as compared with other high-field ESR are that high-field ESR can be done very easily and both microscopic and macroscopic magnetic properties can be obtained at once. Moreover, the transmission technique without using cavity enables us to make multi-frequency ESR measurement in the wide frequency region. We have succeeded in observing ESR from 70 to 315 GHz.