Sr3YCo4O10.5+δ (314-SYCO), with an unusual ordered structure and a high Curie temperature (Tc ≈ 335 K), is attracting increasing attention. Herein, to improve the electrical performance of 314-SYCO, Cu-doped Sr3YCo4−xCuxO10.5+δ (x = 0–0.8) ceramics were prepared using a solid-state reaction method. Systematic research was conducted on both the ordered phase transformation and the effects of Cu doping on the microstructure, electrical transport characteristics, and magnetic properties. For x = 0–0.4, the (103) and (215) planes were observed and combined with Rietveld refinement results for the X-ray diffraction data, confirming the formation of ordered tetragonal Sr3YCo4−xCuxO10.5+δ. This phase was formed with a mass gain of ∼0.8% and heat released at ∼1,042°C. With increasing Cu content, the concentration of hole carriers also increased, leading to a substantial reduction in electrical resistivity. The electrical resistivity decreased by 92–99% at 300 K. The polycrystalline materials have semiconducting behaviour with a three-dimensional Mott variable-range hopping mechanism. For the magnetic properties, a Hopkinson peak was observed at 319 K, and the Tc was approximately 321 K for x = 0. The magnetisation and Tc decreased with increasing Cu content, and a G-type antiferromagnetic-to-ferromagnetic phase transition occurred due to the spin state change for some Co3+ ions from high/intermediate spin to low/intermediate spin. These results lay the groundwork for refinement of the sintering procedure and doping parameters to enhance the performance of 314-SYCO in the context of current applications such as microwave absorbers and solid oxide fuel cell cathodes.

Twin crystal is a common lattice arrangement of crystal structure. The commonly used characterization methods for crystal structure include transmission electron diffraction (TED) pattern and electron backscatter diffraction (EBSD) pattern, but there is currently no specific reference standard for twin crystal. In this research, the mathematical relationship between crystal structure and TED and EBSD patterns of twin was calculated. The characteristics of twin electron diffraction spectrum, as well as the calibration of TED and EBSD patterns, were discussed and analyzed towards the examples of face-centered cubic crystal and body-centered cubic crystal. Overall, our results establish a theoretical calculation standard of diffraction spectrum, which provides a reference for further explorations to characterization of twin crystal structures.