Effects of Mn doping on dielectric properties of ferroelectric relaxor PLZT ceramics

Abstract

A series of PLZT (8/65/35) ceramics with different Mn 2 O 3 concentration (0.01, 0.1, 0.3, 1.0, and 3.0% by weight) have been synthesized to figure out its influence on their dielectric properties. The complex dielectric permittivity ε* ¼ ε 0 Àiε 00 as function of frequency and temperature as well as polarisation loops P(E) have been studied as a function of Mn concentration. It was found that Mn doping is restrained the Vogel-Fulcher law held in the unmodified PLZT compound producing essential change of the dependence of ε* on temperature and frequency and of the shape of P(E). The observed effects are explained by gradual involvement of Debye and Maxwell-Wagner polarisation mechanisms in relaxation processes with the growth of the concentration of Mn concentration admixture. A decrease of the ε'(T) maximum value and shift of the maximum to higher temperatures is observed. The observed effects are attributed to impacts of Mn 2þ and Mn 3þ ions: formation of oxygen vacancies paired with Mn 2þ as dipoles and Jahn-Teller distortion prompted by Mn 3þ ions.

Structure variation and energy storage properties of acceptor‐modified PBLZST antiferroelectric ceramics

“…Upon the addition of Mn, the (110) peak shifts to high angles and then to a low angle in Figure B, indicating that Mn ions have diffused into the PBLZST lattices . Since the sintering temperature is above 1200°C in this study and the valence state of Mn is uncontrolled in air, Mn 2+ , Mn 3+ , and Mn 4+ may coexist . The valence states of Mn ions in the PBLZST ceramics are confirmed by the XPS spectra ().…”

Evolution of Free Volumes in Polycrystalline BaGa2O4 Ceramics Doped with Eu3+ Ions

“…Results obtained by PAL spectroscopy can serve as a research base for the development of independent complementary methods for studying nanosized free volumes in ceramic materials, including neutron and heavy ion irradiated MgAl 2 O 4 spinels [22,27,48], Si 3 N 4 [49], Ge 3 N 4 [50] and AlN [51][52][53], which are especially promising as diagnostic materials for nuclear applications. Other interesting and very important areas are the understanding of porosity, its development and transformation in electrochemical and other devices for energy conversion [54][55][56][57][58][59][60][61][62][63][64].…”

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“…The choice of synthesis methods of ferroelectrics plays an important role on the structural ordering degree and phase composition [11][12][13][14][15]. In most cases, methods of hydrothermal synthesis or plasma sputtering with subsequent heat treatment are used to obtain these types of ceramics [15][16][17][18][19][20][21][22][23][24][25]. However, despite all the positive aspects of these methods, there is a number of limitations imposed on the obtained samples, primarily related to control of structural parameters, as well as the possibility of their variation and obtaining complex composition structures [25][26][27][28][29][30].…”