Accession Number : AD0874917

Title :   Surface Microsonics in Isotropic Media.

Descriptive Note : Quarterly rept. no. 2, 18 Feb-17 May 70,

Corporate Author : RAYTHEON CO WALTHAM MASS RESEARCH DIV

Personal Author(s) : Holland,Melvin G. ; Matsinger,John H. ; Readey,Dennis W.

Report Date : AUG 1970

Pagination or Media Count : 39

Abstract : A program has started on hot-pressed ferroelectric LiNbO3 and LiTaO3. The LiNbO3 has been hot pressed to near theoretical density but attempts to pole the ceramic have been unsuccessful to date. Hot pressing LiTaO3 has just started. Measurement of the surface acoustic wave attenuation has been made on two samples of hot-pressed PZT. The loss at 41 MHz was high, 29 dB/cm in the iron dopant sample and 51 dB/cm in the control; but similar to values obtained in conventionally sintered material. The loss appears to be dominated by contributions from the dielectric losses in the materials. Calculations of the effects of grain boundary scattering have been extended to noncubic crystallites. Problems have been encountered while chemical etching PZT and ZnO during photolithography. These are now under control and positive photoresists are being used. (Author)

Descriptors :   (*ULTRASONIC RADIATION, SUBSTRATES), (*PIEZOELECTRIC CRYSTALS, ULTRASONIC RADIATION), (*FERROELECTRIC CRYSTALS, ULTRASONIC RADIATION), CERAMIC MATERIALS, ISOTROPISM, ATTENUATION, SINGLE CRYSTALS, PROPAGATION, TITANATES, ZIRCONATES, ZINC COMPOUNDS, OXIDES, NIOBATES, LITHIUM COMPOUNDS, LEAD COMPOUNDS, GLASS

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE