title: SAW parameters on Y-cut langasite structured materials.
abstract: This paper presents results and investigations of several new, man-made piezoelectric single crystal, Czochralski-grown substrate materials for surface acoustic waves (SAW) applications. These materials, langanite (LGN), langatate (LGT), Sr3TaGa3Si2O14 (STGS), Sr3NbGa3Si2O14 (SNGS), Ca3TaGa3Si2O14 (CTGS), and Ca3NbGa3Si2O14 (CNGS), have the same structure as langasite (LGS) and are of the same crystal class as quartz. These compounds are denser than quartz, resulting in lower phase velocities. They also have higher coupling. Unlike quartz and lithium niobate, there is no degradation of material properties below the material melting points resulting in the possibility of extreme high-temperature operation (> 1000 degrees C). This paper gives a summary of extracted SAW material parameters for various propagation angles on Y-cut substrates of the six materials. Parameters included are electromechanical coupling, phase velocity, transducer capacitance, metal strip reflectivity, and temperature coefficient of frequency. Using previously published fundamental material constants, extracted parameters are compared with predictions for LGT and LGN. In addition, power flow angle and fractional frequency curvature data are reported for propagation angles on CTGS and CNGS Y-cut substrates that exhibit temperature compensation near room temperature. Detailed descriptions of the SAW parameter extraction techniques are given. A discussion of the results is provided, including a comparison of extracted parameters and an overview of possible SAW applications.
authors.affiliation: School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, FL 32816-2450, USA. rick.puccio@ieee.org
authors.forename: Derek
authors.initials: D
authors.lastname: Puccio
authors.forename: Donald C
authors.initials: DC
authors.lastname: Malocha
authors.forename: Nancy
authors.initials: N
authors.lastname: Saldanha
authors.forename: Mauricio Pereira
authors.initials: MP
authors.lastname: da Cunha
mesh_terms: D000162:Acoustics; D003198:Computer Simulation; D008420:Manufactured Materials / Q000032:analysis*; D008422:Materials Testing; D008956:Models, Chemical; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation; D017640:Silicates / Q000737:chemistry*; D013499:Surface Properties
chemical_list: C470742:La3Ga5SiO14; D017640:Silicates