Two decades following the discovery of thermally stable elastic properties of La₃Ga₅SiO₁₄ crystal and coining of the term “langasite” (a review)

Abstract

Twenty years ago, in December 2003, the Editorial Board of Technical Physics received a paper entitled “The New Piezoelectric Material “Langasite” La₃Ga₅SiO₁₄ with Zero Temperature Coefficient of the Elastic Vibration Frequency.” This paper marked the beginning of a new stage in the development of piezo-and acoustoelectronics. During the twenty years following the publication of this paper, langasite crystals have led to the formation of a new trend in the preparation of materials with preset piezoelectric properties. Such an achievement in the field of piezoelectric materials science has been unheard of ever since 1921, when piezoelectric properties of α quartz were used to construct rf oscillators. Various piezoelectric devices, which form an inseparable part in the progress of modern communication devices, television, radars, and several kinds of defence technology are being produced by the thousands in developed countries all over the world. It is hard to overestimate the importance of producing miniaturized wideband filters based on new langasite-type materials for mobile communication to transmit video images in real time. This review contains a brief description of the initial stage of discovery and research of the unique piezoelectric properties of a langasite crystal and the fabrication of the first devices based on it.