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PbMg1/3Nb2/3O3dielectric aging in the freezing temperature region
S B Vakhrushev1, E Yu Koroleva1, A Yu Molokov1
1Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St.-Petersburg 195251, Russia.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|November 23, 2023
Summary
Aging in lead magnesium niobate (Pb(Mg1/3Nb2/3)O3) relaxors was studied around freezing temperatures. New data reveals aging effects above freezing, attributed to multi-polar nanoregions, offering insights into relaxor behavior.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Dielectric Spectroscopy
Background:
- Relaxor ferroelectrics, particularly Pb(Mg1/3Nb2/3)O3, exhibit complex aging phenomena.
- Previous studies focused mainly on low-temperature, glass-like behavior, leaving a gap in understanding around freezing temperatures.
Purpose of the Study:
- To systematically investigate the dielectric spectra evolution of Pb(Mg1/3Nb2/3)O3 around its freezing temperature (Tf ≈ 240 K).
- To characterize aging effects both below and above the freezing point across a wide frequency range (10⁻¹ Hz to 10⁶ Hz).
Main Methods:
- Dielectric spectroscopy measurements were performed on Pb(Mg1/3Nb2/3)O3.
- Data analysis covered frequencies from 10⁻¹ Hz to 10⁶ Hz, both below and above Tf.
- Investigated time-dependent changes in dielectric spectra to observe aging.
Main Results:
- Confirmed waiting time-frequency scaling below Tf (≈ 50 Hz), with deviations at higher frequencies possibly due to complex relaxing entities.
- Observed aging effects above Tf in a limited frequency range below the dielectric loss peak.
- Aging manifested as hardening and narrowing of dielectric loss spectra and decreased dielectric strength over time.
Conclusions:
- Aging above Tf is linked to the formation of degenerate polar nanoregions (multi-PNRs) spanning multiple chemically ordered regions.
- These multi-PNRs are larger than single-region PNRs and their freezing contributes to the observed spectral changes.
- The study provides crucial data on relaxor aging dynamics near the freezing transition.
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