Role of developing L10 chemical order on the (001)-texture formation of (Fe1-xCux)Pt films grown on amorphous substrates

We study the technologically important (0 0 1)-texture formation in 10 nm thick (Fe0.9Cu0.1)(52)Pt-48 and, as reference, Fe49Pt51 alloy films. The samples are grown on SiO2(200 nm)/Si(0 0 1) substrates at ambient temperature by pulsed laser deposition. Subsequent rapid thermal processing (RTP) at 650 degrees C for various time steps drives the initially nanocrystalline and chemically disordered films into the tetragonal L1(0) phase accompanied by a strong (0 0 1)-texture leading to perpendicular magnetic anisotropy. The fundamental role of the chemical order during short-time annealing as an additional source of strain in the films is experimentally addressed. The structural and magnetic results indicate selective grain growth leading to the (0 0 1)-texture. Strongly prolonged annealing, however, leads to a reorientation of grains towards the (1 1 1)-texture pointing to the increasing importance of surface energies when the initial strain has released.