Volume 88, Issue 4, 15 August 2000
Index of content:
- DIELECTRICS AND FERROELECTRICITY (PACS 77)
88(2000); http://dx.doi.org/10.1063/1.1305859View Description Hide Description
Epitaxial (LNSMO) thin films and heterostructures have been grown on (001) substrates by the pulsed laser deposition method. The oxygen concentration in the LNSMO films is quite sensitive to the deposition oxygen pressure and can be controlled during the fabrication process. It is, however, stable against in situ postdeposition thermal treatments. Consequently, the resistivity and the metal-semiconductor transition temperature of the LNSMO films can be tuned and fixed during film growth. Electrical measurements on the Pt/PZT/LNSMO ferroelectric capacitor show a remnant polarization of ∼35 μC/cm2 and a coercive field of 30–40 kV/cm at low driving voltages. Switching endurance tests suggest no polarization loss up to about bipolar switching cycles. The advantages of using epitaxial LNSMO films as the semiconducting channel in an all-perovskite ferroelectricfield-effect transistor are discussed.
Alternating current electrical properties of antiferroelectric lead zirconate thin films by pulsed excimer laser ablation88(2000); http://dx.doi.org/10.1063/1.1303723View Description Hide Description
In situ crystalline lead zirconate (PZ) thin films were deposited on platinum metallized silicon substrates, using a 248 nm KrF pulsed excimer laserablation technique. The antiferroelectricity in PZ thin films was confirmed by means of P vs E and C vs measurements. The maximum observed saturated polarization was 44 μC/cm2 at an applied field of 200 kV/cm. The calculated forward and backward switching fields were 71 and 154 kV/cm, respectively. The dielectric phase transition temperature was at ∼219 °C with zero dc bias and was increased to 290 °C in the presence of 4 V dc bias. Detailed comprehensive study was done on PZ thin films to understand the charge carrier transport with respect to frequency domain of dielectric and ac conductivity measurements. Effect of simultaneous dc bias on the frequency response of the dielectric dispersion and ac conductivity studies were done to understand the nature of charge carrier transport and their activation energies. The calculated activation energies, from ac conductivity and conductance measurements, in the absence of external dc bias were 0.42 and 0.37 eV, respectively. Measurements with the simultaneous application of 4 V dc bias gave two activation energy values 0.38 and 1.76 eV, respectively. The lower and higher activation energies were attributed to the shallow and deep trap energies respectively.