Hyperfine effects and electron spin relaxation of 51V4+ doped into scandium orthosilicate Sc228SiO5: CW and pulsed X-band electron spin resonance studies

The scandium orthosilicate monocrystal Sc228SiO5 (SSO) doped with 51V isotope in small concentrations (0.005% at.) was studied. We used continuous wave (CW) and pulsed electron spin resonance (ESR) methods with frequencies in the X-band range (9.3–9.8 GHz). From the orientational dependencies of the CW ESR spectra we found the following: the hyperfine interaction of the vanadium ions is very anisotropic and the Zeeman interaction is almost isotropic with principal values of the g – tensor near electron g – factor. In addition to that, we found that the charge state of vanadium ions is V4+. The directions of the principal axes of the A and g tensors were determined. The phase memory and spin–lattice relaxation were measured. It was found that the temperature dependence of the spin–lattice relaxation time can be approximated by the sum of direct and Aminov–Orbach processes with decent accuracy. The phase memory time stays in the microseconds range even at the temperature T = 30 K.