Preparation and thickness dependence of magnetic properties of (1 1 1)-oriented Mg_1.5FeTi_0.5O₄ spinel films on sapphire by pulsed laser deposition technique

Thin films of (1 1 1)-oriented Mg_1.5FeTi_0.5O₄ spinel have been successfully prepared by a pulsed laser deposition (PLD) technique on α-Al₂O₃ (0 0 0 1) substrates. The value of the lattice parameter of the (1 1 1) out-of-plane and the Néel temperature of the films depend on the film thickness. The spin-glass behavior has been observed with a freezing temperature of 100 K, which is 80 K higher than that of the bulk material. This freezing temperature is reduced by increasing the oxygen pressure during film preparation. These results show that the PLD technique is promising not only for obtaining thin films of oxide materials under a wide range of conditions but also for controlling the magnetic properties of films.