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Broad-band dielectric response of 0.5Ba(Ti0.8Zr0.2)O3-0.5 (Ba0.7Ca0.3)TiO3 piezoceramics: soft and central mode behaviour

Kamba, Stanislav ; Simon, E. ; Skoromets, V. ; Bovtun, Viktor ; Kempa, Michael ; Pokorny, J. ; Savinov, M. ; Koruza, Jurij ; Malič, Barbara (2016)
Broad-band dielectric response of 0.5Ba(Ti0.8Zr0.2)O3-0.5 (Ba0.7Ca0.3)TiO3 piezoceramics: soft and central mode behaviour.
In: Phase Transitions, 89 (7-8)
doi: 10.1080/01411594.2016.1199800
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

Dielectric properties of 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics were probed in the frequency range from 10 Hz to 100 THz in a broad temperature range (10-900 K). Polar soft phonon observed in infrared spectra softens with cooling; however, below 500 K, its frequency becomes temperature independent. Simultaneously, a central mode activates in terahertz and microwave spectra; and it actually drives the ferroelectric phase transitions. Consequently, the phase transitions strongly resemble a crossover between the displacive and order-disorder type. The central mode vanishes below 200 K. The dielectric relaxation in the radiofrequency and microwave range anomalously broadens on cooling below TC1, resulting in the nearly frequency independent dielectric loss below 200 K. This broadening comes from a broad frequency distribution of ferroelectric domain wall vibrations. Raman spectra revel new phonons below 400 K, i.e. already 15 K above TC1. Several weak modes are detected in the paraelectric phase up to 500 K in Raman spectra. Activation of these modes is ascribed to the presence of polar nanoclusters in the material.

Typ des Eintrags: Artikel
Erschienen: 2016
Autor(en): Kamba, Stanislav ; Simon, E. ; Skoromets, V. ; Bovtun, Viktor ; Kempa, Michael ; Pokorny, J. ; Savinov, M. ; Koruza, Jurij ; Malič, Barbara
Art des Eintrags: Bibliographie
Titel: Broad-band dielectric response of 0.5Ba(Ti0.8Zr0.2)O3-0.5 (Ba0.7Ca0.3)TiO3 piezoceramics: soft and central mode behaviour
Sprache: Englisch
Publikationsjahr: 29 Juni 2016
Verlag: Taylor&Francis
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Phase Transitions
Jahrgang/Volume einer Zeitschrift: 89
(Heft-)Nummer: 7-8
DOI: 10.1080/01411594.2016.1199800
URL / URN: http://www.tandfonline.com/doi/full/10.1080/01411594.2016.11...
Kurzbeschreibung (Abstract):

Dielectric properties of 0.5Ba(Ti0.8Zr0.2)O3-0.5(Ba0.7Ca0.3)TiO3 ceramics were probed in the frequency range from 10 Hz to 100 THz in a broad temperature range (10-900 K). Polar soft phonon observed in infrared spectra softens with cooling; however, below 500 K, its frequency becomes temperature independent. Simultaneously, a central mode activates in terahertz and microwave spectra; and it actually drives the ferroelectric phase transitions. Consequently, the phase transitions strongly resemble a crossover between the displacive and order-disorder type. The central mode vanishes below 200 K. The dielectric relaxation in the radiofrequency and microwave range anomalously broadens on cooling below TC1, resulting in the nearly frequency independent dielectric loss below 200 K. This broadening comes from a broad frequency distribution of ferroelectric domain wall vibrations. Raman spectra revel new phonons below 400 K, i.e. already 15 K above TC1. Several weak modes are detected in the paraelectric phase up to 500 K in Raman spectra. Activation of these modes is ascribed to the presence of polar nanoclusters in the material.

Freie Schlagworte: Dielectric spectroscopy; leadfree piezoelectrics; soft mode; central mode; phonons; polar nanoregions; infrared; terahertz; Raman spectroscopy
Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Nichtmetallisch-Anorganische Werkstoffe
Hinterlegungsdatum: 30 Jun 2016 06:00
Letzte Änderung: 18 Jun 2020 06:10
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