Magnetic properties and microstructure of (0 0 1) oriented Ag/FePt, Ag/FePt/Ag films

This study fabricates FePt film with (0 0 1) preferred orientation on a glass substrate by rapid thermal annealing (RTA) at 800 °C for 5 min. The ultrathin Ag capped layer and seed layer were inserted to reduce the ordering temperature. The (0 0 1) preferred orientation formed in Ag/FePt bilayer or Ag/FePt/Ag trilayer when annealed at 700 °C for 5 min. From transmission electron microscopy (TEM) images, the interface Ag atoms diffused and segregated to form the Ag phase with L10 lattice, creating vacancies at the FePt lattice. The phase transformation activation energy was reduced as compared to single layer FePt film. Phase transformation strain dominated during ordering and grain growth. The formation of (0 0 1) preferred orientation on glass substrate was achieved by rapid ordering and recrystallization during post annealing.