High-temperature superconducting block materials (HTSB) have been widely used in a variety of applications and devices in the past several decades. Because of their superior electrical and thermal properties, HTSB materials are ideal for high-performance electronic devices and equipment. The microstructure of HTSB materials is a critical factor in determining its performance. This paper introduces the microstructure of some common HTSB materials, such as YBCO, BT-BSCCO and MgB2.
YBCO is a new member of the family of cuprate superconductors. Its structure consists of an alternating stack of YBa2Cu3O7-d layers that form a lattice of CuO2 planes. In the lattice, there are two types of CuO2 planes: the more electrically-inactive apical oxygens (AO) and the active basal oxygens (BO). The BO planes contain two Cu ions, two apical oxygens, and two basal oxygens; the AO planes contain four Cu ions and four apical oxygens. Additionally, the structure includes Y-O chains formed from Y and O atoms. The alternating arrangement of the two types of CuO2 planes gives rise to a strong charge modulation pattern.
BT-BSCCO is a type of multilayer high-temperature superconductor. The basic structure of BT-BSCCO consists of four B-BSCCO layers and four intervening BT layers. Each B-BSCCO layer consists of planar arrays of Cu and Bi ions, surrounded by oxygen anions, while each BT layer consists of a bilayer of copper and copper-oxygen (Cu-O) complex. The stacking of these layers produces a superlattice structure with alternating Cu-O bilayers and B-BSCCO layers. It is proposed that the Cu-O layers are responsible for binding the B-BSCCO layer planes together, while also providing extra electrons to the superconductor.
Finally, MgB2 is a type of boride superconductor. Its structure consists of alternating layers of an MgB2 host lattice and percolated networks of B molecules. The MgB2 host lattice is highly anisotropic, with two distinct lattice directions. The interlocking structure of the host lattice and the B molecules provides additional stability to the material. This results in MgB2 having a higher critical temperature than other boride superconductors. Moreover, the presence of these two crystalline components gives MgB2 a unique combination of electrical and thermal properties.
In conclusion, the microstructure of HTSB materials plays a large role in determining the performance of these materials. YBCO, BT-BSCCO and MgB2 are some of the most common HTSB materials, each of which have distinct microstructures that give them their individual performance characteristics.
