Accession Number : ADA267074

Title :   Nanocomposites for Electronic Applications. Volume 2.

Descriptive Note : Final rept. 1 Jan 90-31 Dec 91,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB

Personal Author(s) : Cross, L. E.

Report Date : 14 JUN 1993

Pagination or Media Count : 173

Abstract : Work on this program and associated studies on the ONR program on 'Piezoelectric and Electrostrictive materials for Transducer Applications' has lead to a significantly improved understanding of the fundamental mechanisms in Relaxor Ferroelectrics. For the perovskite Lead Magnesium Niobate which is the prototype for many other relaxor perovskites, the self limiting nonstoichiometric ordering of Mg/Nb ions is shown to be the symmetry breaking key to the onset of micropolar regions at the Burns temperature well above the dielectric maximum. The simple paraelectric behavior at high temperature is shown to be modified by cooperation on cooling, leading to a Vogel:Fulcher type condensation into a glass like state at low temperature

Descriptors :   *DIELECTRICS, *FERROELECTRICITY, *RELAXATION, NIOBATES, LEAD COMPOUNDS, MAGNESIUM COMPOUNDS, SPECTROSCOPY.

Subject Categories : Physical Chemistry
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE