Speakers
Description
Nuclear magnetic resonance (NMR) probes nuclear spins, while electron spin
resonance (ESR) probes electron spins through transitions between Zeeman-split
energy levels in a magnetic field. Relaxation constants $T_1$, $T_2$, and $T_2^*$ are key
parameters in pulsed ESR measurements and spin dynamics [1]. Convention-
ally, these relaxation constants are measured using the same microwave (MW)
antenna that excites the electron-spin transitions, limiting spatially localized
detection.
Our group has already measured continuous-wave ESR with an electron
probe inside the transmission electron microscope (TEM) [2]. Here, we aim
to expand our technique to measure the relaxation constants with the electron
probe positioned close to the sample. For this, we use a custom-made setup,
including a TEM sample holder [3]. Inside the microscope, the electron spins are
polarized using the objective lens field ($B_0 \approx 170 \ \mathrm{mT}$). For the measurement
of relaxation constants, we plan to use standard sequences of π
2 and π pulses,
in order to obtain spin echo and related signals [4].
This method could enable spatially resolved ESR relaxation measurements
inside an electron microscope, opening new possibilities for nanoscale studies of
magnetic and quantum materials.
References
[1] F. Bloch PhysRev 1946, 70, 460.
[2] A. Jaroˇs, M. S. Seifner, J. Toyfl, B. Czasch, S. Beltr´an-Romero, I. C. Bicket,
P. Haslinger ACS Nano 2026, 20, 3443.
[3] A. Jaroˇs, J. Toyfl, A. Pupi´c, B. Czasch, G. Boero, I. C. Bicket, P. Haslinger
Ultramicroscopy 2025, 278, 114224.
[4] Meiboom, S. and Gill, D. Review of Scientific Instruments 1958, 29, 691.