THE FERROELECTRIC-ANTIFERROELECTRIC TRANSITION AND DIELECTRIC PROPERTIES IN THE TERNARY SYSTEM PbZrO$sub 3$-PbHfO$sub 3$-PbTiO$sub 3$
Variations in phase behavior between the binary systems PbZrO/sub 3/-- PbTiO/sub 3/ and PbHfO/sub 3/-- PbTiO/sub 3/ previously were reported. This behavior led to the investigation of the ferroelectric-antiferroelectric transition and dielectric properties in the ternary system PbZrO/sub 3/-PbHfO/sub 3/PbTiO/sub 3/. The investigation included compositions up to 10 mole% PbTiO/sub 3/ on the PbHfO/sub 3/- PbTiO/sub 3/ binary and the ompositions on the PbZrO/sub 3/- PbTiO/sub 3/ binary were prepared for comparison. Ceramic specimens were prepared using a moderately pure hafnium oxide (98.5% HfO/sub 2/). The raw materials were mixed and then calcined for six hours at 850 c- C to form the desired compositions. Ceramic properties including bulk density, apparent porosity, and weight change after firing are reported for all compositions. Dielectric constant and dissipation factor were measured as a function of temperature and anomalies or peaks in the curve of dielectric constant versus temperature were used as indications of phase transitions. To determine the electrical nature of the phases present, the relationship between applied electric field and dielectric displacement was observed with the aid of a Sawyer-Tower circuit. Pyroelectric discharge measurements were made on selected samples. X-ray investigation was limited to a study of the room temperature phases present. Phase diagrams determined from electrical measurements are presented for the two binaries investigated. An important feature of the diagiam for the high hafnate region of the PbHfO/sub 3/-- PbTiO/sub 3/ binary was that for a narrow compositional region between Pb(Hf/sub .95/Ti/sub .05/)O/sub 3/ and Pb(Hf/sub .90/Ti/sub .10/)O/sub 3/ an antiferroelectric phase exists at a higher temperature than the ferroelectric phase. This was determined from the fact that Pb(Hf/sub .925/Ti/sub .075/)O/sub 3/ exhibited a polymorphic inversion from a ferroelectric to an antiferroelectric with ascending temperature. This order of phase transition, ferroelectric to antiferroelectric, was contrary to the phase behavior in the Pb(Zr/sub .5/Hf/sub .5/)O/sub 3/-- PbTiO/sub 3/ and transition at the morphotropic phase boundary was antiferroeiectric to ferroelectric. Two antiferroelectric phases were shown to exist for compositions near the PbHfO/sub 3/- PbZrO/sub 3/ binary. Photographs of polarization as a function of applied electric field are shown for selected compositions and values of remnant polarization and coercive field tabulated. For a given concentration of PbTiO/ sub 3/, additions of PbHfO/sub 3/ to PbZrO/sub 3/ caused an increase in the coercive field and decreased the remnant polarization. (TCO)
- Research Organization:
- Originating Research Org. not identified
- NSA Number:
- NSA-17-025272
- OSTI ID:
- 4711752
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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Related Subjects
CERAMICS
CHEMISTRY
DIELECTRICS
ELECTRIC DISCHARGES
ELECTRIC FIELDS
FERROMAGNETIC MATERIALS
HAFNIUM COMPOUNDS
HAFNIUM OXIDES
HIGH TEMPERATURE
LEAD COMPOUNDS
LEAD OXIDES
PHASE DIAGRAMS
PHOTOGRAPHY
POLARIZATION
POROSITY
PYROMETERS
QUALITATIVE ANALYSIS
TEMPERATURE
THERMOMETERS
TITANIUM OXIDES
X RADIATION
ZIRCONIUM COMPOUNDS
ZIRCONIUM OXIDES