Influence of the substrate choice on the L1 phase formation of post-annealed Pt/Fe and Pt/Ag/Fe thin films

Abstract

Pt/Fe and Pt/Ag/Fe layered films were deposited by DC magnetron sputtering on MgO(001), SrTiO3(001), and Al2O3(0001) single crystalline substrates at room temperature. The films were post-annealed between 623 K and 1173 K for 30 s in flowing N2 atmosphere. The onset of the L10-FePt phase formation in films deposited on MgO(001) and SrTiO3(001) substrates was observed after annealing between 773 and 873 K, while chemical L10 ordering sets in for Pt/Fe bilayers on Al2O3(0001) at lower temperatures accompanied by strong (001)-texture. It is concluded that elastic stress, arising from the difference in thermal expansion coefficients between film and substrate, promotes ordering and texture formation.