EPR operation

First, one places a single-crystal sample on a rotating stage within the spectrometer’s microwave cavity. Then, one fixes the microwave frequency and sweeps the external magnetic field to determine the resonance positions, where microwave absorption occurs. Next, we calculate the effective g-value for each observed peak using the resonance condition. Since the defects are anisotropic, their resonance positions depend on their orientation w.r.t. the applied magnetic field. Finally, one rotates the crystal by small stages. At each new angle, we repeat the magnetic field sweep and record the new resonance positions. The figure is then obtained by plotting the calculated g-values on the y-axis against the rotation angle on the x-axis.