Basic thermophysical parameters of langasite (La3Ga5SiO14), langatate (La3Ta0.5Ga5.5O14), and catangasite (Ca3TaGa3Si2O14) single crystals in a temperature range of 25 to 1000°C

Kugaenko, O. M.; Uvarova, S. S.; Krylov, S. A.; Senatulin, B. R.; Petrakov, V. S.; Бузанов, О. А.; Егоров, В. Н.; Sakharov, S.

doi:10.3103/s1062873812110123

Cited by 25 publications

(10 citation statements)

References 4 publications

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“…Besides this, the electrical resistivity of Mo (5.5 μΩ·cm) [ 19 ] is lower than that of Pt (10.8 μΩ·cm) [ 19 ]. Thermal-stress-induced damages can be reduced because of the lower coefficient of thermal expansion (CTE) of Mo (4.8 × 10 −6 at room temperature) [ 19 ], which is close to that of the applied substrate (3.3 × 10 −6 at room temperature of Ca 3 TaGa 3 Si 2 O 14 (CTGS) substrate [ 20 ]), as compared to the much higher CTE of Pt (8.8 × 10 −6 at room temperature) [ 19 ]. In addition to the exceptional physical properties of Mo, mechanical properties, such as high strength and creep resistance, are notable advantages for their use as IDT materials for SAW temperature sensors [ 21 ].…”

Section: Introductionmentioning

confidence: 99%

Stress and Microstructure Evolution in Mo Thin Films without or with Cover Layers during Thermal-Cycling

et al. 2020

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The intrinsic stress behavior and microstructure evolution of Molybdenum thin films were investigated to evaluate their applicability as a metallization in high temperature microelectronic devices. For this purpose, 100 nm thick Mo films were sputter-deposited without or with an AlN or SiO2 cover layer on thermally oxidized Si substrates. The samples were subjected to thermal cycling up to 900 °C in ultrahigh vacuum; meanwhile, the in-situ stress behavior was monitored by a laser based Multi-beam Optical Sensor (MOS) system. After preannealing at 900 °C for 24 h, the uncovered films showed a high residual stress at room temperature and a plastic behavior at high temperatures, while the covered Mo films showed an almost entirely elastic deformation during the thermal cycling between room temperature and 900 °C with hardly any plastic deformation, and a constant stress value during isothermal annealing without a notable creep. Furthermore, after thermal cycling, the Mo films without as well as with a cover layer showed low electrical resistivity (≤ 10 μΩ·cm).

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Section: Introductionmentioning

confidence: 99%

Stress and Microstructure Evolution in Mo Thin Films without or with Cover Layers during Thermal-Cycling

et al. 2020

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“…As distinct from the studies of optical, mechanical and thermal properties [7,13,[16][17][18][19][20][21], so far there is insufficient data about the electrical conductivity and anisotropy mechanism for langasite crystals. Electrical conductivity of lanthanum gallium silicate is low and its value limits the operation reliability of piezoelectric element in different devices.…”

Section: Introductionmentioning

confidence: 99%

Electrical conductivity and structural conditionality of ion transfer in langasite La-=SUB=-3-=/SUB=-Ga-=SUB=-5-=/SUB=-SiO-=SUB=-14-=/SUB=-:Mn

Sorokin

Golovina

Константинова

2022

Physics of the Solid State

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The temperature dependence of the static electrical conductivity sigmadc(T) of a single crystal of lanthanum gallium silicate (langasite) La3Ga5SiO14 activated with an impurity of Mn (1000 ppm) has been studied by impedance spectroscopy. Impedance measurements of La3Ga5SiO14 (sp. gr. P321, Z=1) were carried out along crystallographic axes a (double symmetry axis) and c (triple symmetry axis). It was found that the values of sigma|| a are significantly higher than the electrical conductivity sigma|| c, the anisotropy of the electrical conductivity is sigma|| a/sigma|| c=170 at 773 K. The activation energy of electrotransport is Esigma=0.75±0.05 and 1.09±0.02 eV along the a and c axes, respectively. The electrical conductivity mechanism has an ionic nature and an impurity character; oxygen vacancies VOoo are the most probable current carriers. Keywords: lanthanum gallium silicate, langasite family, single crystal, electrical conductivity, anisotropy.

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“…Another high-temperature stable piezoelectric substrate of the same LGS family is Ca 3 TaGa 3 Si 2 O 14 (CTGS) [19,20,21]. This material has better piezoelectric properties, such as higher effective piezoelectric coefficient at high temperature.…”

Section: Introductionmentioning

confidence: 99%

“…This material has better piezoelectric properties, such as higher effective piezoelectric coefficient at high temperature. The crystals have better quality due to the lower Ga content, higher electrical resistivity, higher mechanical strength and a lower thermal expansion anisotropy as compared to langasite [20,21,22,23]. This relatively newer substrate material is lesser known and thin films on it are not extensively studied yet.…”

Section: Introductionmentioning

confidence: 99%

“…The choice of refractory metal W, over the commonly used inert Pt, is based on it having a high melting point (3422 °C) which would lead to minimal creep-related damaging effects (the activation energy for self-diffusion at 1000 °C for W is ~ 6 eV while for Pt is ~ 3 eV [26]), its lower electrical resistivity (5.49 μΩ ·cm) as compared to Pt (10.6 μΩ·cm), closer CTE (4.5 × 10 −6 K) to LGS (a 11 = 5.63 × 10 −6 K) and CTGS (a 11 = 3.3 × 10 −6 K) [20] than for Pt (8.8 × 10 −6 K). In addition, W has exceptional thermal shock resistance due to its low CTE combined with its high thermal conductivity (174 W·m −1 ·K −1 ) which for Pt is much lower (72 W·m −1 ·K −1 ) [27].…”

Section: Introductionmentioning

confidence: 99%

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Tungsten as a Chemically-Stable Electrode Material on Ga-Containing Piezoelectric Substrates Langasite and Catangasite for High-Temperature SAW Devices

et al. 2016

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Thin films of tungsten on piezoelectric substrates La3Ga5SiO14 (LGS) and Ca3TaGa3Si2O14 (CTGS) have been investigated as a potential new electrode material for interdigital transducers for surface acoustic wave-based sensor devices operating at high temperatures up to 800 °C under vacuum conditions. Although LGS is considered to be suitable for high-temperature applications, it undergoes chemical and structural transformation upon vacuum annealing due to diffusion of gallium and oxygen. This can alter the device properties depending on the electrode nature, the annealing temperature, and the duration of the application. Our studies present evidence for the chemical stability of W on these substrates against the diffusion of Ga/O from the substrate into the film, even upon annealing up to 800 °C under vacuum conditions using Auger electron spectroscopy and energy-dispersive X-ray spectroscopy, along with local studies using transmission electron microscopy. Additionally, the use of CTGS as a more stable substrate for such applications is indicated.

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Basic thermophysical parameters of langasite (La3Ga5SiO14), langatate (La3Ta0.5Ga5.5O14), and catangasite (Ca3TaGa3Si2O14) single crystals in a temperature range of 25 to 1000°C

Cited by 25 publications

References 4 publications

Stress and Microstructure Evolution in Mo Thin Films without or with Cover Layers during Thermal-Cycling

Stress and Microstructure Evolution in Mo Thin Films without or with Cover Layers during Thermal-Cycling

Electrical conductivity and structural conditionality of ion transfer in langasite La-=SUB=-3-=/SUB=-Ga-=SUB=-5-=/SUB=-SiO-=SUB=-14-=/SUB=-:Mn

Tungsten as a Chemically-Stable Electrode Material on Ga-Containing Piezoelectric Substrates Langasite and Catangasite for High-Temperature SAW Devices

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