Giant dielectric permittivity and electromechanical strain in thin film materials produced by pulsed-laser deposition

Thin film materials with a giant dielectric permittivity er′≈10 000 and an electromechanical strain of Δh/h≈8% are produced by pulsed-laser deposition. Composite targets containing various different oxides such as BaTiO3, BaO2, BaCO3, and TiO2 powder embedded in the polymer polytetrafluoroethylen (PTFE) are employed for laser ablation. The dielectric permittivities of the films show strong relaxation at frequencies above 10 kHz, a pronounced dependence on layer thickness, and a frequency-dependent activation at lower temperatures. Composite targets as well as films produced from BaF2/PTFE targets show only low permittivities with er′<20 and do not reveal such phenomena.

[1]  D. Bäuerle.  Laser Processing and Chemistry , 1996 .

[2]  R. Y. Ting,et al.  Space-charge-enhanced electromechanical response in thin-film polyurethane elastomers , 1997 .

[3]  Fátima Esteban-Betegón,et al.  New Percolative BaTiO3–Ni Composites with a High and Frequency-Independent Dielectric Constant (εr ≈ 80000) , 2001 .

[4]  Zhang,et al.  Giant electrostriction and relaxor ferroelectric behavior in electron-irradiated poly(vinylidene fluoride-trifluoroethylene) copolymer , 1998, Science.

[5]  S. Bauer,et al.  Chemical composition and charge stability of highly crystalline pulsed-laser-deposited polytetrafluoroethylene films on metal substrates , 2001 .

[6]  Johannes Heitz,et al.  Pulsed-laser deposition of crystalline Teflon (PTFE) films , 1998 .

[7]  S. Bauer-Gogonea,et al.  Flexible ceramic–polymer composite films with temperature-insensitive and tunable dielectric permittivity , 2002 .

[8]  A. Jonscher.  Dielectric relaxation in solids , 1983 .

[9]  High dielectric permittivity in AFe1/2B1/2O3 nonferroelectric perovskite ceramics (A=Ba, Sr, Ca; B=Nb, Ta, Sb) , 2002, cond-mat/0209015.

[10]  I. Krakovský,et al.  A few remarks on the electrostriction of elastomers , 1999 .

[11]  F. Xia,et al.  An all-organic composite actuator material with a high dielectric constant , 2002, Nature.

[12]  H. Kliem,et al.  Dispersive ionic space charge relaxation in solid polymer electrolytes. I. Experimental system polyethylene oxide , 2002 .

[13]  Margaret L. Gardel,et al.  Giant dielectric constant response in a copper-titanate , 2000 .

[14]  Reinhard Schwödiauer,et al.  Charge stability of pulsed-laser deposited polytetrafluoroethylene film electrets , 1998 .

[15]  R. T. Pack,et al.  The static dipole polarizabilities of all the neutral atoms in their ground states , 1971 .