Pressure, temperature, and electric field dependence of phase transformations in niobium modified 95/5 lead zirconate titanate

Abstract

Ceramic niobium modified 95/5 lead zirconate-lead titanate (PZT) undergoes a pressure induced ferroelectric to antiferroelectric phase transformation accompanied by an elimination of polarization and a volume reduction. Electric field and temperature drive the reverse transformation from the antiferroelectric to ferroelectric phase. The phase transformation was monitored under pressure, temperature, and electric field loading. Pressures and temperatures were varied in discrete steps from 0 MPa to 500 MPa and 25 °C to 125 °C, respectively. Cyclic bipolar electric fields were applied with peak amplitudes of up to 6 MV m−1 at each pressure and temperature combination. The resulting electric displacement–electric field hysteresis loops were open “D” shaped at low pressure, characteristic of soft ferroelectric PZT. Just below the phase transformation pressure, the hysteresis loops took on an “S” shape, which split into a double hysteresis loop just above the phase transformation pressure. Far above the phase transformation pressure, when the applied electric field is insufficient to drive an antiferroelectric to ferroelectric phase transformation, the hysteresis loops collapse to linear dielectric behavior. Phase stability maps were generated from the experimental data at each of the temperature steps and used to form a three dimensional pressure–temperature–electric field phase diagram.

Large barocaloric effect and pressure‐mediated electrocaloric effect in Pb0.99Nb0.02(Zr0.95Ti0.05)0.08O3 ceramics

“…PZT consists of five major phases including a ferroelectric tetragonal phase (PT>48%), an anti‐ferroelectric orthorhombic phase (PT<5%), a high‐temperature anti‐ferroelectric tetragonal phase, two ferroelectric rhombohedral phases (5%<PT<48%) and a paraelectric cubic phase that exists above the Curie temperature . Our selected composition containing 95% PZ and 5% PT lies at the phase boundary between the anti‐ferroelectric and ferroelectric rhombohedral phases . Depending upon the nature (electric, thermal and mechanical) and intensity of actuation provided, a phase transition can be initiated .…”

“…Depending upon the nature (electric, thermal and mechanical) and intensity of actuation provided, a phase transition can be initiated . Literature indicates that application of electric field and temperature stabilize the ferroelectric phase while application of compressive stresses favors anti‐ferroelectric phase . A study by Berlincourt et al discussed phase stability diagrams for PZT systems and also explored the effects of substitution/doping on the same .…”

“…A study by Berlincourt et al discussed phase stability diagrams for PZT systems and also explored the effects of substitution/doping on the same . It was reported that donor dopants affected hysteresis parameters and phase stability, with small amounts of Nb favoring the FE phase formation . Since the transition representing ferroelectric (FE) ↔ anti‐ferroelectric (AFE) entails a large change in polarization and structural arrangement, a concomitantly large change in entropy is also expected .…”

“…The obtained values of polarization vs electric field ( P ‐ E ) hysteresis loops were analyzed using the modified Maxwell's relation to determine caloric effects. Complete details including the experimental results presented here have been reported previously …”

Soft modes condensation in Raman spectra of (Pb–La)(Zr–Sn–Ti)O3 ceramics

“…At this time, the ceramics is transformed from a FE phase to an AFE phase. 2,3 In addition, by rising temperature, the AFE phase could be transformed to the PE one above Curie temperature.…”