Curie constant in relaxor ferroelectrics Pb(Zn_1/3Nb_2/3)O₃–8%PbTiO₃

Abstract

The dielectric permittivity along the [001] c direction of the pseudocubic coordinate in Pb(Zn 1/3 Nb 2/3 )O 3 -8%PbTiO 3 (PZN-8%PT) was investigated in a wide temperature range of 30-640 °C. The determination of the Curie constant in PZN-8%PT was attempted, using the dielectric permittivity above the Burns temperature, to evaluate the bulk property in the ferroelectric phase as an average structure with reduced heterogeneity. It was confirmed that the reported temperature dependence of the spontaneous polarization can be quantitatively well reproduced on the basis of the Landau-type free energy.

Temperature–field phase diagram and spontaneous polarization in Pb(Sc1/2Ta1/2)O3 single crystal

“…The permittivity in PST never follows the Curie-Weiss law near the transition temperature because of the diffuse phase transition, but it should satisfy the Curie-Weiss law when the level of inhomogeneity due to the polar nanoregion decreases at high temperatures. 42) Using T 0 = 10.2 °C obtained from the results of our experiment, we can obtain the Curie constant C = 1.30 × 10 5 °C (see the solid line in Fig. 6).…”

Improvement of ferroelectric random access memory manufacturing margin by employing Pt/AlOxbottom electrode for the La-doped Pb(Zr,Ti)O3ferroelectric capacitor

“…Among perovskite materials, lead zirconate titanate [PZT, Pb(Zr,Ti)O 3 ] and its modified materials including La-doped PZT (PLZT) are the most promising and the most extensively studied materials. [11][12][13][14][15] The crystalline state of PZT is significantly affected by temperature, pressure, and ambient species in postdeposition annealing (PDA). 4,11,12,14,[16][17][18] Therefore, the crystallization mechanism during PDA has been widely reported for PZT prepared by sol-gel deposition, 16,[19][20][21][22][23][24] pulsed-laser deposition (PLD), 25,26) and metal-organic deposition (MOD).…”

Dielectric tunability in Pb(Sc1/2Ta1/2)O3single crystals

“…On the other hand, we have investigated the temperaturefield phase diagram in a Pb(Zn 1=3 Nb 2=3 )O 3 -xPbTiO 3 (PZN-xPT) mixed system where PZN-xPT shows large dielectric and piezoelectric responses near the morphotropic phase boundary (MPB) located near x = 9%. [13][14][15][16][17][18][19] Ishibashi and Iwata proposed a theoretical model for such physical properties near the MPB based on the Landau-Devonshiretype free energy, where the dielectric permittivity perpendicular to the spontaneous polarization becomes extremely high, since the anisotropy of the free energy in the parameter space decreases. [20][21][22] In a series of our previous studies, we found that the ferroelectric critical endpoint (CEP) exists on the temper-ature-field phase diagram in the PZN-xPT system, 18) and that PZN-xPT near the CEP indicates a dielectric tunability higher than 90%, although unfortunately the operation temperature is much higher than room temperature.…”