Peculiarities of dc magnetic field pulse influence on nuclear spin echo in magnets

The dependences of two-pulse echo signal intensities on the parameters of dc magnetic field pulses are measured in a number of magnets: Li0.5Fe2.5-xZnxO4 (x < 0.25) (enriched by 57Fe isotope up to 96.8 %), NiMnSb, Co2MnSi, La1-xCaxMnO3 (x = 0.2; 0.25) and polycrystalline Co. It is found that there are two types of dependences of these signals on application time of such pulses relative to application time of exciting radio-frequency pulses. The influence of mechanisms of domain structure and dynamical frequency shift on the observed peculiarities of the investigated signals is discussed