Structure and AC conductivity of polycrystalline Pb(Cd1/3Nb2/3)O3

• Autorzy: Bąk, W. , Kajtoch, C. , Mroczka, K. , Wójcik, K.
• Języki publikacji: EN

Abstrakty

EN

Purpose: Purpose of this work was to determine crystalline structure and ac electric conductivity of polycrystalline sample Pb(Cd1/3Nb2/3)O3 (PCN) in paraelectric phase. Controversies involving uncertainties of phase transition character were the motivation of our experimental investigation: roentgenostructural, electron microscopy (SEM) and dielectric (ε') as well as electric (δ') spectroscopy. Design/methodology/approach: Polycrystalline PCN samples were prepared using hot pressing method. X-ray measurements had been performed with use of DRON3 apparatus (Cu Kα, monochromator: monocrystal LiF, at detector NaI side) with jump of 2O angle accounting for 0.02deg within a range 10-120deg. Structure images were made at room temperature with a use of electron microscope Philips SEM 525M. Dielectric measurements were made with a use of automatic measuring system Quatro Cryosystem 4.0 and Agilent Precision LCR meter HP4284A equipped with WinDETA 5.62 software Novocontrol. Before measurements, polycrystalline PCN samples were refreshed by annealing at 700 K. Next, electric measurements were carried out under cooling with 2 K/min speed. Findings: It was established that cubic phase is present within the whole range of temperatures (173 K-723 K) applied in our measurements. The polar component of the electric conductivity was dominate below the Tm temperature (Tm - temperature at which the maximal value of dielectric permittivity takes place). Above this temperature, activation energy (φ) is falling down, along increasing frequency of measuring field. Research limitations/implications: Changes of AC conductivity of PCN were interpreted in terms of polar regions properties evolution. Originality/value: Results obtained have broad the knowledge about phase transitions occurring without crystal structure change, but involving freezing of polar regions under cooling.

Słowa kluczowe

PL

ferroelektryki; przejścia fazowe; polaryzacja; właściwości elektryczne

EN

ferroelectrics; phase transition; polarization; electrical properties

• Czasopismo: Archives of Materials Science and Engineering
• Rocznik: 2008
• Tom: Vol. 33, nr 2
• Strony: 75-78
• Opis fizyczny: Bibliogr. 15 poz.

Twórcy

autor

Bąk, W.

autor

Kajtoch, C.

autor

Mroczka, K.

autor

Wójcik, K.

• Institute of Physics, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków, Poland,

Bibliografia

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