High coercivity SmCo based films made by pulsed laser deposition

Abstract

Films of SmCo based materials exhibiting high intrinsic coercivities and smooth hysteresis loops have been prepared by pulsed laser deposition (PLD) onto moderately heated substrates. Films directly crystallized from SmCo5 targets onto 375 °C substrates exhibited a maximum Hc=11.3 kOei at a pulse repetition rate of 10 Hz with lower coercivities for both lower and higher pulse repetition rates. In the present case the films were deposited onto polycrystalline substrates. The films exhibited a very small grain size of less than 1 μm diameter, were mirrorlike, and shadow deposited films were relatively particulate free under scanning electron microscope examination. Shadowed PLD deposition was used for the best films. Laser wavelengths of 193 and 248 nm were used with pulse repetition rates from 5 to 50 Hz. Films grown without shadowing exhibited a great deal of particulate contamination. The hysteresis loops of such nonshadowed films were constricted and exhibited drops in the 4πM values upon demagnetization. To our knowledge this is the first reporting of high coercive force SmCo based films deposited by PLD exhibiting single phase type hysteresis loops.