LGT Crystals 

Simple description：

Langatate (LGT), with the chemical formula of La3Ga5.5Ta0.5O14, is a novel non-ferroelectric piezoelectric crystal that exhibits a range of unique physical and chemical properties.

Detailed Description：

The Langatate (LGT) crystal is a novel non-ferroelectric piezoelectric crystal with unique physical and chemical properties. It belongs to the trigonal crystal system, with a space group of P321 and a point group of 32. The LGT crystal exhibits no phase transition from room temperature to its melting point, and possesses excellent piezoelectric, opto-rotatory, and electro-optic properties. Therefore, it is widely used as a new type of opto-rotatory-electro-optic Q-switch material. Additionally, LGT crystals feature a non-centrosymmetric structure, a wide transmission band, and a high laser damage threshold, making them promising candidates for applications in nonlinear optics.

LGT crystals can be prepared by methods such as the Czochralski method, and high-quality crystals can be easily obtained. They exhibit high piezoelectric constants and good electromechanical coupling coefficients, as well as excellent temperature stability. These superior properties render LGT crystals valuable for applications in electronics, optics, sensing, and other fields. For instance, they can be used to fabricate intermediate frequency filters, high-temperature sensors, surface acoustic wave (SAW) devices, acoustic resonators, and piezoelectric sensors.

Advantages：

1. High Electromechanical Coupling Factor: Compared to traditional artificial crystals, LGT exhibits a higher electromechanical coupling factor, providing better performance in electro-acoustic conversion and mechanical vibration sensing.
2. Phase Stability: LGT remains phase-stable from room temperature to its melting point (approximately 1470℃), demonstrating good thermal stability and structural stability, suitable for applications in high-temperature environments.
3. High Resistivity: LGT possesses high resistivity, especially at high temperatures, maintaining excellent electrical insulation and stability in electronic devices.
4. Excellent Piezoelectric Properties: LGT exhibits strong piezoelectric effects with piezoelectric constants superior to many other piezoelectric materials, suitable for the production of piezoelectric sensors, filters, and other devices.
5. Good Optical Properties: LGT possesses optical rotation and electro-optic properties, making it a suitable material for novel optical rotation-electro-optic Q-switches. Additionally, its non-centrosymmetric structure, wide transmission band, and high laser damage threshold offer broad application prospects in nonlinear optics.
6. Ease of Preparation: LGT crystals can be prepared into large-size single crystals through traditional methods such as the Czochralski method, facilitating industrial production and application.

Application fields：

1. Intermediate Frequency Filters: The excellent piezoelectric properties and temperature stability of LGT crystals make them ideal materials for the production of intermediate frequency filters. These filters are widely used in wireless communications, radar, television, and other fields.
2. High-Temperature Sensors: LGT crystals are suitable for the production of high-temperature sensors due to their phase stability from room temperature to the melting point, high resistivity, and thermal stability. These sensors can work stably in high-temperature environments and provide accurate temperature and pressure measurements.
3. Surface Acoustic Wave (SAW) Devices: The piezoelectric properties of LGT crystals make them a preferred material for the production of SAW devices. SAW devices have a wide range of applications in mobile communications, signal processing, and other fields.
4. Acoustic Resonators: The high-frequency vibration characteristics and stability of LGT crystals make them ideal for the production of acoustic resonators. These resonators play an important role in oscillation circuits, frequency control, and other fields.
5. Piezoelectric Sensors: Various piezoelectric sensors, such as pressure sensors and acceleration sensors, can be produced using the piezoelectric effect of LGT crystals. These sensors have a wide range of applications in industrial automation, automobile manufacturing, and other fields.
6. Nonlinear Optical Devices: The non-centrosymmetric structure, wide transmission band, and high laser damage threshold of LGT crystals make them potentially valuable for the production of nonlinear optical devices. These devices may play an important role in laser technology, optical communications, and other fields.

Specifications:

Parameter Name	Value
Chemical Composition	La3Ga5.5Ta0.5O14
Crystal Structure	Trigonal
Space Group	P321
Point Group	32
Density	6.13 g/cm³ (or 6.151 g/cm³, slightly different in different literature)
Melting Point	Approximately 1470 ℃
Mohs Hardness	6.5 (or 6.6, slightly different in different literature)
Unit Cell Parameters	a=8.228 Å, c=5.129 Å (or a=0.82200±0.0021 nm, c=0.51217±0.0015 nm, slightly different in different literature)
Resistivity	1.5×10^8 Ω·cm @540 ℃
Young’s Modulus	YE11=11×1010 N/m²
Piezoelectric Constants	-d11=6.5 pC/N, d14=4.7 pC/N (or d11=+7.1×10(-12) C/N, slightly different in different literature)
Thermal Expansion Coefficient	a11=6.087×10(-6)/℃ (or α11=6.3435×10(-1), α33=4.6036×10(-1), slightly different in different literature)
Pyroelectric Effect	None
Electrode Material	Au (chrome flash gold)