Nanocrystalline Sm-Co-Cu(Ni) thin films with giant coercivity

Nanostructured Srn-Co, Sm-Co-C;u, Sm-Co-Ni thin films have been obtained by crystallizing the as-deposited amorphous films which were sputtered onto C r buffer layers. Room temperature coercivity increases from less than 100 O e in the amorphous state up to 42 kOe in a SmCo2Cu3 Sample annealed 30 min. at 550 degrees C. initial magnetization curves showed a behavior character istic of uniform domain wall pining. Magnetic viscosity measurements indica ted that the switching volume is of the same order as the Sm(Co,Cu)(5) crys tallites size. Remanence Measurements showed that interparticulate interact ions were magnetizing and rather independent of the crystallization static These data pointed to domain wall pinning at the high anisotropy Sm-C'.o pr ecipitates as the origin of the huge coercivity in the annealed films. (C) 1999 Acta Metallurgica Inc.