Abstract: This invention discloses a thermal head having a resistive layer of a thin Ta-Si-O film containing more than 45 mol % and at most 75 mol % of a silicon oxide in terms of SiO.sub.2, and a method of manufacturing a thermal head by sputtering a sintered target in vacuum atmosphere at an argon gas partial pressure of 10.times.10.sup.-3 Torr to 80.times.10.sup.-3 Torr so as to obtain the resistive layer.

Abstract: The elastic surface wave device comprises a piezoelectric substrate having a dielectric constant of .epsilon..sub.2, a dielectric film having a dielectric constant of .epsilon..sub.1 and a thickness of h, and deposited on the piezoelectric substrate, and an inter-digital type input-ouput transducer formed on the dielectric film. The ratio of the dielectric constants .epsilon..sub.1 /.epsilon..sub.2, and a function 2.pi./.lambda..multidot.h proportioned to the thickness of the dielectric film are selected to satisfy a condition established in a frustum shaped region bounded by coordinate points P (.epsilon..sub.1 /.epsilon..sub.2 = 1/5,(2.pi./.lambda.).multidot.h = 0.1), Q(.epsilon..sub.1 /.epsilon..sub.2 = 1/5,(2.pi./.lambda.).multidot.h = 0.00016), R(.epsilon..sub.1 /.epsilon..sub.2 = 1/500,(2.pi./.lambda.).multidot.h = 0.0004), and S(.epsilon..sub.1 /.epsilon..sub.2 = 1/500, (2.pi./.lambda.).multidot.h = 0.006) on a graph wherein the ratio .epsilon..sub.1 /.epsilon..sub.