Spontaneous trasition between relaxor and ferroelectric states in lanthanum-modified lead zirconate titanate (6-7)/65/35

• Published in: Japanese Journal of Applied Physics Vol. 33; no. 9A; pp. 4940 - 4945
• Main Authors: KRUMINS, A, SHIOSAKI, T, KOIZUMI, S
• Format: Journal Article
• Language: English
• Published: Tokyo Japanese journal of applied physics 1994
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Dielectric properties of solids and liquids; Dielectric, piezoelectric, ferroelectric and antiferroelectric materials; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Exact sciences and technology; Niobates, titanates, tantalates, pzt ceramics, etc; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Permittivity (dielectric function); Physics; Temperature dependence; Frequency dependence; Transparency; Inorganic compounds; Phase transformations; Light scattering; Transition element compounds; Long-range order; Doped materials; Titanates; Ceramics; Lead compounds; Experimental study; Relaxation; Quantity ratio; Ferroelectricity; PLZT; Lanthanum additions; Aging; Zirconates; Permittivity
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.33.4940

Dielectric and light scattering measurements are performed in lanthanum modified lead zirconate titanate (PLZT) (6–8)/65/35 hot-pressed ceramics in order to refine the phase diagram. A relaxor-ferroelectric phase transition takes place in PLZT (6–7)/65/35 at temperature lower than the temperature of the dispersive dielectric constant maximum. At this temperature the size of polar regions “ a ” essentially increases up to a >λ (=0.63 µ m). The appearence of ferroelectric long-range order in PLZT with decreased concentration of La ions is explained by larger coupling between ferroelectrically active BO 6 octahedrons due to the smaller concentration of defects and higher dielectric constant.