Dielectric and electromechanical properties of Pb(Mg1/3,Nb2/3)O3–PbTiO3 thin films grown by pulsed laser deposition

Abstract

Pulsed laser deposition was used to grow thin films of several compositions from the Pb(Mg1/3,Nb2/3)O3–PbTiO3 (PMN–PT) solid solution as dielectric layers in thin film capacitor structures. They were found to display functional behavior characteristic of relaxors, with the only significant difference between thin film and bulk being a severely reduced dielectric permittivity. Room temperature polarization loops showed a general increase in both the remanent polarization and absolute magnitude of the polarization for a given field with PT content. The electric field-induced strain was primarily examined by in situ x-ray diffraction and although fields greater than 20 MV m−1 were applied to the films, the maximum observed strain was only ∼0.3%, considerably less than the 1.4% seen in single crystal samples. Piezo-response atomic force microscopy studies were consistent in that the macroscopic effective piezoelectric coefficient d33, was found to differ from single crystal measurements by an order of magnitude. However, electrostrictive coefficients (Q33), were found to be comparable to published values for both PMN–PT single crystals and ceramics, ranging between 1 and 9×10−2 C−4 cm2. Consequently, it seems that the relatively poor strain response in these thin films is intimately linked to the reduced permittivity and not to a fundamental difference in the electrostrictive coefficients between bulk and thin film.

Investigation of the electrocaloric effect in a PbMg2/3Nb1/3O3-PbTiO3 relaxor thin film

“…4 PbMg 2/3 Nb 1/3 O 3 ͑PMN͒ is a well-known relaxor that develops long-range dipolar order by adding a certain amount of the ferroelectric perovskite PbTiO 3 ͑PT͒. [6][7][8] The phase diagram of the mixed solid solution ͑1−x͒PMN-xPT has generated some controversy, particularly in x Ͻ 0.3 where relaxor compositions form. The existence of a structural phase transition in relaxor PMN-PT is debatable.…”

Deposition conditions and electrical properties of relaxor ferroelectric Pb(Fe1∕2Nb1∕2)O3 thin films prepared by pulsed laser deposition

“…[7][8][9][10][11][12] The said studies have revealed that the dielectric constant maximum of bulk specimens ͑K max Ϸ 30 000͒ are notably reduced in thin-film form ͑K max Ϸ 3000͒. [13][14][15] Compared with PMN-PT, only a few papers have been published on PFN thin layers. Nonepitaxial films with superior properties have been reported by Sedlar and Sayer 16 using a sol-gel method.…”

Room temperature giant electrocaloric properties of relaxor ferroelectric 0.93PMN-0.07PT thin film

“…[13][14][15] The phase diagram of the mixed solid solution (1−x) PMN-xPT has generated some controversy, particularly in x 0.3 where relaxor compositions form. Permittivity measurements of a 0.93PMN-0.07PT thin film show a broad maximum near 35 • C, and an anomaly at the depolarizing temperature of 18 • C on heating only, suggesting a dipolar glass-relaxor phase transition.…”