A lead-free non-ferroelectric piezoelectric glass-ceramic for high temperature surface acoustic wave devices

Effect of Partial Ba Substitutions on the Crystallization of Sr2TiSi2O8 (STS) Glass–Ceramics and on the Generation of a SAW Signal at High Temperatures

“…The four compositions investigated are presented in Table 1 . The composition Ba(0) corresponds to ST 1.3S + 0.2K 2 O + 0.1Al 2 O 3 previously investigated [ 31 , 40 ]. In the compositions Ba(10), Ba(25) and Ba(50), 10 at.%, 25 at.% and 50 at.% of barium are respectively substituted to the strontium.…”

“…The surface acoustic wave device used for the tests was realized on a 60 × 25 × 5 mm glass–ceramic substrate ( Figure 4 ). The IDTs were realized by a two-step metal-coating by sputtering and laser ablation, as it is detailed in Reference [ 31 ]. A 40 nm–thick adhesion layer of constantan (55 wt.% Cu, 45 wt.% Ni) is deposited prior to the 200 nm–thick platinum conductive layer.…”

“…Sputtering is realized thanks to a BAL-TEC MED 020 equipment (Leica Microsystems, Wetzlar, Germany) working under an argon atmosphere. The targeted frequency for the IDTs is 2 MHz, the same as that of the SAW device successfully tested in Reference [ 31 ].…”

“…In their paper, Davis et al [ 30 ] highlight the potential of fresnoite glass–ceramics for applications, such as accelerometers for turbine engines or pressure sensors. In a previous paper [ 31 ], we demonstrated the ability of an STS glass–ceramic to generate and propagate SAW up to a temperature of 900 °C.…”

“…In addition, High temperature XRD shows the stability of the STS phase in this glass–ceramic up to 1000 °C. It is this composition that we recently used to demonstrate the possibility to realize and operate a SAW device at a high temperature [ 31 ]. Despite significant variations in the output signal amplitude with temperature, it remains readable up to 900 °C.…”