High-frequency electron-spin-resonance measurements on Mn x Mg1-xO (x = 1.0×10-4) and DPPH at very low temperatures
: Y Ishikawa, K Ohya, S Miura, Y Fujii, S Mitsudo, T Mizusaki, A Fukuda, A Matsubara, H Kikuchi, T Asano, H Yamamori, S Lee, S Vasiliev
: Jonas Bylander, Tomas Löfwander, Maciej Misiorny
: International Conference on Low Temperature Physics
Publisher: Institute of Physics Publishing
: 2018
: Journal of Physics: Conference Series
: 28th International Conference on Low Temperature Physics (LT28) 9–16 August 2017, Gothenburg, Sweden
: Journal of Physics: Conference Series
: 1
: 969
: 6
: 1742-6588
DOI: https://doi.org/10.1088/1742-6596/969/1/012111
: https://research.utu.fi/converis/portal/detail/Publication/32080607
We have developed a millimeter-wave electron-spin-resonance (ESR) system for very low temperatures (T
< 1 K) that can be employed for nuclear-magnetic-resonance
measurements by using dynamic nuclear polarization. The system uses a
Fabry-Pérot resonator that works in the frequency range of 125 – 130 GHz
and covers the temperature range of 0.09 – 6.5 K. We have performed ESR
measurements in the frequency around 128 GHz by using Mn x Mg1-x O (x = 1.0 × 10-4)
and free-radical samples of 1, 1-diphenyl-2-picrylhydrazyl (DPPH),
because these samples have been proposed as field and sensitivity
markers. Temperature dependence of the ESR signal intensity for Mn x Mg1-x O
shows anomalies originating from magnetic order are found around 3.5 – 4
K. We estimate the sensitivity of the system for ESR detections to be 6
× 1013 spins/G at 5.8 K. Because DPPH shows no
observable shift in the magnetic field, we propose it as a useful
standard marker for ESR measurements at very low temperatures.
