Pulsed laser deposition of chromium oxides thin films: chemical stabilization by capping and doping

摘要

The half-metallic ferromagnetic chromium dioxide (T_c = 390 K) is a prospective material for spintronics applications. We employed pulsed laser deposition (PLD) to grow thin films of various chromium oxides. The experiments have been carried out in oxygen at different dynamical pressures, using a KrF~* laser source (λ = 248nm, τ_(FWHM) ≥ 30 ns), various chromium oxide targets, such as CrO_3, Cr_8O_(21) (the latter ones both pure and doped with Y and Sb respectively, for stabilization purposes) and sapphire substrates (c-cut). We optimized the laser fluence. To avoid CrO_2 reduction to Cr_2O_3 in very thin films when kept in atmospheric air, we applied a protection with gold. X-ray diffraction, electron microscopy and Raman spectroscopy evidenced uniform films containing CrO_2.