High sensitive detection of sub-THz ESR using the cantilever and the pulsed magnetic field

We have succeeded in observing electron spin resonance (ESR) in the sub-THz region using the cantilever and the pulsed magnetic field for the first time. ESR measurement beyond 0.5 THz, whose resonance field is about 18 T for the typical g-value of g=2, requires the pulsed magnetic field which enables the field beyond the maximum field of the superconducting magnet. High sensitive sub-THz ESR is very important for applications to various fields, such as molecular nano-magnets, EL materials, metal proteins etc., because it has many advantages like the high spectral resolution, observation of short relaxation materials, and observation beyond the zero-filed splitting etc. As the conventional metal cavity technique, which is the typical high sensitive detection technique for the conventional X-band (9 GHz) ESR, is difficult in the pulsed magnetic field, the high sensitive detection using the cantilever is a breakthrough for the future high sensitive THz ESR which definitely requires the pulsed magnetic field.