FORMATION MECHANISMS AND PROPERTIES OF ELECTRON-SPIN ECHOES IN SOLIDS

In addition to the ordinary Hahn mechanism of electron spin echoes (ESEs), i.e. the non-linear amplitude-dependent excitation of spin precession, two new mechanisms, namely amplitude-dependent shift DELTAomega(M(z)) of resonance frequency (pulling) and amplitude-dependent damping GAMMA(M(z)) = T2(-1)(M(z)) (M(z) is the z component of the magnetization), are proposed. The latter two mechanisms are due to the effect of instantaneous diffusion. A qualitative picture and a quantitative theory of EsEs in solids are elaborated, taking into account all three non-linear mechanisms. A new method based on the modulation effect of echo damping is presented to obtain the parameters T1, T2 and DELTAomega. The modulation effect is due to the simultaneous action of the three non-linear mechanisms.