Pulsed laser ablation deposition of yttrium iron garnet and cerium-substituted YIG films

Yttrium iron garnet (YIG) thin films were grown on gadolinium gallium garne t substrates using pulsed laser ablation deposition (PLAD) with a XeCl exci mer laser. Films were grown up to over 2 mu m thick, however cracking prove d to be a problem for films over 1 mu m thick. The lattice parameter(s) of the films and the substrates were measured and indicated that the film/subs trate structure was bending to accommodate strain due to the lattice mismat ch. The films had saturation magnetisation values close to that of bulk YIG and were isotropic in the film plane. The magnetisation data also indicate stress-induced uniaxial isotropy. The ablation conditions were varied to p roduce uncracked films with low droplet densities. YIG melts incongruently during the laser ablation process and cone-like structures form on the abla tion target lowering the ablation rates. Cerium-substituted YIG alms were a lso grown in both oxygen and argon atmospheres, substituting cerium into YI G increases the lattice parameter and hence reduces the strain. The Ce-YIG film grown in argon was greenish indicating that cerium was in the desired oxidation state. (C) 2000 Elsevier Science B.V. All rights reserved.