Nanoscale Multiferroic Properties at Room Temperature of Lead Zirconate Titanate Iron Tantalate for Memory Device Applications

The electrical behavior of modified soft lead zirconate titanate (PZT) ceramics has been studied as a function of temperature at different direct current (dc) electric fields and grain sizes. As ferroelectrics, such as PZT, are highly polarizable materials, poling, depolarization, and electric conduction contribute to the total electrical current, which leads to anomalous electrical behavior as a function of temperature. The PZT appeared to have a high pyroelectric coefficient, and it was found that the displacement current hides the conduction current near room temperature. The (long-time) steady-state electrical resistivity of the soft PZT used has a typical, relatively high value of 3.6 × 1012 Ω·cm near room temperature. The resistivity above the Curie temperature was two orders of magnitude lower than the room temperature. The resistivity decreases with increasing grain size probably due to the increased Pb vacancy concentration resulting as a consequence of a higher sintering temperature. The values of activation energies suggest that the charge carriers at high temperature are mainly oxygen vacancies. At intermediate temperature, the electrical behavior is controlled by the counteracting effect of depolarization and conduction. Considering the pyroelectric effect and the conduction, it was thus possible to explain the electrical behavior of this soft PZT ceramic over the temperature range considered.

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Fatigue Properties of Lanthanum Strontium Manganate–lead Zirconate Titanate Epitaxial Thin Film Heterostructures Produced by a Chemical Solution Deposition Method

Journal of Materials Research ◽

10.1557/jmr.2000.0221 ◽

2000 ◽

Vol 15 (7) ◽

pp. 1546-1550 ◽

Cited By ~ 15

Author(s):

Frank McNally ◽

Jin Hyeok Kim ◽

F. F. Lange

Keyword(s):

Lead Zirconate Titanate ◽

Fatigue Behavior ◽

Memory Device ◽

Lead Zirconate ◽

Fatigue Properties ◽

Device Structure ◽

Lanthanum Strontium Manganate ◽

Chemical Solution Deposition Method ◽

Lanthanum Strontium ◽

Zirconate Titanate

A liquid-precursor process was used to produce an epitaxial all-oxide ferroelectric memory device structure. The lanthanum strontium manganate–lead zirconate titanate–lanthanum strontium manganate (LSMO–PZT–LSMO) structure used for this device shows excellent polarization and fatigue behavior with a remnant polarization Pr of 42 µC/cm2 and a coercive field Ec of 68 keV. The polarization was found to only slightly degrade after over 1010 fatigue cycles. This behavior is contrasted with epitaxial PZT using a metal top electrode. In addition, the use of a top LSMO electrode was a sufficient barrier to Pb loss during heating to allow subsequent (or prolonged) heat treatments that would generally lead to Pb loss.

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Erratum: “An investigation on the leakage current and time dependent dielectric breakdown of ferroelectric lead–zirconate–titanate thin film capacitors for memory device applications” [Appl. Phys. Lett. 69, 4011 (1996)]

Applied Physics Letters ◽

10.1063/1.119268 ◽

1997 ◽

Vol 70 (8) ◽

pp. 1058-1058

Author(s):

Jia-lin Chen ◽

Hong-ming Chen ◽

Joseph Ya-min Lee

Keyword(s):

Thin Film ◽

Lead Zirconate Titanate ◽

Dielectric Breakdown ◽

Memory Device ◽

Lead Zirconate ◽

Time Dependent ◽

Time Dependent Dielectric Breakdown ◽

Thin Film Capacitors ◽

Device Applications ◽

Titanate Thin Film

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Lead Zirconate Titanate Via Reaction Sintering of Hydroxide Precursors

Journal of Materials Research ◽

10.1557/jmr.1999.0201 ◽

1999 ◽

Vol 14 (4) ◽

pp. 1503-1509 ◽

Cited By ~ 6

Author(s):

Xue Junmin ◽

John Wang

Keyword(s):

High Temperature ◽

Lead Zirconate Titanate ◽

Room Temperature ◽

Sintered Density ◽

Nitrate Solution ◽

Lead Zirconate ◽

Processing Route ◽

Sintering Behavior ◽

Zirconate Titanate ◽

One Step

Lead zirconate titanate (PZT) has been successfully fabricated via a unique one-step sintering processing route, which is simpler than the traditional precursor-calcinationmilling- pelleting-sintering route and is able to deliver an enhanced sintered density at a much reduced sintering temperature. The hydroxide precursor was prepared by coprecipitation from a mixed nitrate solution containing Pb2+, Zr4+, and Ti4+ ions, and it was then compacted into pellets without being calcined at a low temperature. The precursor pellets were dehydrated at 400, 500, and 600 °C for 4 h, respectively, followed by an isostatic pressing at 350 MPa, prior to being sintered at a high temperature. Dehydration temperature has a large impact on the sintering behavior of these hydroxide-derived PZT ceramics. The PZT dehydrated at 400 °C was seriously cracked when sintered at temperatures ranging from 950 to 1150 °C, due to the incomplete dehydration. A sintered density of 99.2% theoretical density was obtained at 1050 °C for 2 h for the powder pellet dehydrated at 500 °C for 4 h. It exhibits a dielectric constant of 1024 and a dielectric loss of 2.1% at a frequency of 1 kHz at room temperature. A calcination at a too-high temperature, e.g., 600 °C, results in a reduction in the sinterability of the precipitate-derived PZT ceramic.

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