MULTIPLE NUCLEAR-SPIN ECHO IN THIN POLYCRYSTALLINE FERROMAGNETIC-FILMS

The formation of multiple nuclear spin echo signals has been studied i n thin ferromagnetic polycrystalline films of 3d-metals and their allo ys with induced anisotropy at temperatures between 2.2 and 300 K using two-pulse and three-pulse excitation. A method is proposed for the ex perimental determination of the contributions made by different mechan isms to the formation of spin-echo signals in magnets with strongly in homogeneous Zeeman and quadrupole interactions, It is shown that in fe rromagnets with a high rf field gain at the nucleus, the frequency mod ulation mechanism has a substantial influence in observations of nucle ar spin-echo signals at nuclei with a high magnetic moment, even at li quid-helium temperatures. (C) 1998 American Institute of Physics.