A comparative study of rare earth–iron thin films prepared by TEA CO2 and excimer laser ablation deposition

Thin rare earth–iron magnetic films have been deposited by pulsed laser ablation deposition utilising TEA CO2 and excimer laser sources. The effect of stationary and rotating targets on the film composition has been studied. It has been found that using a wide range of fluences (19–66 J cm−2) and a rotating target, the TEA CO2 laser system produces terbium deficient films. There is also a concomitant non-stoichiometric track left on the target. The composition of films produced by ArF laser ablation of rotating TbFe2 targets over a fluence range of 0.2–0.8 J cm−2 is strongly fluence dependent. By keeping the target stationary, the film composition becomes largely fluence independent and stoichiometric deposition occurs. Data are presented to support mechanisms that may explain these observations; it is hypothesised that phase separation during the melt/resolidification cycle and possible resputtering of deposited material is responsible.