Currently the most intensively investigated tungsten bronze niobate is strontium barium niobate (Sr_xBa_1-xNb₂O₆, SBN) crystal. SBN crystals have solid solution of tetragonal tungsten bronze structure when 0.25≤x≤0.75, of which the space group is P4bm and the point group is 4mm. SBN single unit cell has 10 NbO6 octahedrons, and only five alkaline earth ions filling the 10 voids, wherein Sr^{2 +} and Ba^{2 +} ions occupy portions A1 and A2, position C is empty, which is called non-filled tungsten bronze structure. SBN single crystal are more generally SBN: 61 (x = 0.61) or SBN: 60, this composition crystal is relatively easy to grow and easy to obtain high-quality and large-size crystals. In addition, the Curie point of SBN crystal decreases with increasing x, which decreases down to SBN: 75 of 60 ℃ from SBN: 25 of 200 ℃.

 

The most commonly method to grow SBN is Czochralski method, larger size SBN crystal material can be grew with this method. Crystal of SBN: 61 melting point is about 1510 ℃, the general use of silica-alumina rod frequency heating or resistance heating crystal growing equipment for growing, growing container Pt crucible. In addition the use of technology such as automatic path to maintain the solid - liquid interface of the flat, which helps to get the large size high-quality crystal.

 

Kubota based on the Czochralski method, with the cooling crucible base method to grow larger size crystals of SBN: 61. 1968 Lee reported that SBN crystal growth with decline crucible method, this method can ensure the equal diameter and eliminate crystal growth streak, the growth of the crystals thermal stress is large, but it can be reduced the portion of the thermal in stress crystal growth by annealing. In addition, the growth method of doped SBN crystal and undoped SBN crystals are consistent, but cracking and growth of striped crystal growth are more likely to show up because of doping, and pay attention to adjust the process parameters (pulling rate is low) during the process. Effective electro-optic coefficient of SBN crystals is large, so it is a good electro-optical crystal, and it has a relatively large pyroelectric coefficient, which has been made into the infrared detection element. However, due to the low curie point of SBN commonly used, which greatly limits its wider application in the higher temperature range. The basic physical parameters of the SBN crystals as follows: