The workhorse in HTS technology is YBCO with YBa2Cu3O7 as chemical formula. In reality a slight Copper excess is preferred in order to get optimized superconducting properties. The surplus of Copper results in small copperoxide precipitates on the surface of the YBCO film. We call such films S-Type as they are often used in the field of superconducting electronics, like SQUIDs or SQIFs. Typically the patterned linewidth here is in the range of few microns only.
For most microwave, power or MRI applications the typical linewidth is larger than 10µm and so the surface roughness is not crucial. In such cases we prefer also to add Yttrium which leads to incorporation of tiny Y2O3 particles in the films that act as pinning centers. Such films show highest critical current density and low surface resistance. As a result of the Yttrium excess, the films appear porous. We name such films M-Type, what comes from "Microwave"
Excellent microwave performance, porous surface, enhanced pinning
Microwave devices, high jc-applications, FCL
Typical superconducting specs:
Tc = 87,5 K
jc(77K) ≥ 2.5 MA/cm2
Rs < 300 µΩ (@77K, 10 GHz, 600 nm)
Warranted specs (thickness > 300 nm)
Tc > 87 K
jc(77K) > 2 MA/cm2
Rs < 500 µΩ (@77K, 10 GHz, 600 nm)