Lead-free relaxor thin films of tungsten bronze symmetry

Dominique Michau (1) , Annie Simon (1) , Mario Maglione (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

We have processed Ba_1+x/2LaNb_5-xTi_xO₁₅ thin films using radio-frequency magnetron sputtering. Using XRD, SEM, x-ray microprobe and RBS, the polycrystalline films have been optimized as to reach the nominal composition. Dielectric experiments have been performed on ceramics and thin films for frequencies between 100 Hz and 5 MHz in the temperature range 100-420 K. In the most stoichiometric films, relaxor behaviour is evidenced whose features are similar to those of ceramics of the same composition. Such an agreement between ceramics and thin films relaxors is only rarely reported in lead-free materials. Moreover, the relaxor state was reported in perovskite films and our present report broadens the range of structures in which it can occur.

Mots clés: Deposition by sputtering; X-ray diffraction; Permittivity (dielectric function); Dielectric loss and relaxation; Dielectric thin films; Scanning electron microscopy

Domaines: Matériaux

Dominique Michau, Annie Simon, Mario Maglione. Lead-free relaxor thin films of tungsten bronze symmetry. Journal of Physics D: Applied Physics, 2009, 42 (7), 075407 (7 p.). ⟨10.1088/0022-3727/42/7/075407⟩. ⟨hal-00368390⟩