Elastic wave device, high-frequency front-end circuit, and communication apparatus

An elastic wave device comprising:

• a piezoelectric layer;
• an interdigital transducer electrode disposed on the piezoelectric layer;
• a high-acoustic-velocity member in which an acoustic velocity of a bulk wave that propagates through the high-acoustic-velocity member is higher than an acoustic velocity of an elastic wave that propagates through the piezoelectric layer;
• and
• a low-acoustic-velocity film in which an acoustic velocity of a bulk wave that propagates through the low-acoustic-velocity film is lower than an acoustic velocity of an elastic wave that propagates through the piezoelectric layer, the low-acoustic-velocity film being located between the high-acoustic-velocity member and the piezoelectric layer;
• wherein
• the piezoelectric layer is made of lithium tantalate;
• the interdigital transducer electrode includes metal layers;
• each of the metal layers includes an Al metal layer and a metal layer having a density higher than Al;
• and
• expression 1 is satisfied:
• 301.74667−10.83029×TLT−3.52155×TELE+0.10788×TLT2+0.01003×TELE2+0.03989×TLT×TELE≥0 expression 1
• where λ represents a wavelength defined by an electrode finger pitch of the interdigital transducer electrode, TLT (%) represents a normalized film thickness of the piezoelectric layer and is obtained by normalizing a film thickness of the piezoelectric layer to the wavelength λ, and TELE (%) represents a normalized film thickness of the interdigital transducer electrode in terms of Al and is obtained by normalizing a film thickness of the interdigital transducer electrode in terms of Al to the wavelength λ, the film thickness of the interdigital transducer electrode in terms of Al being calculated by dividing a sum of products of densities and thicknesses of the respective metal layers by a density of Al.