Microstructural and dielectric properties of Ba0.45Mg0.05Sr0.5-xCaxTiO3 high entropy ceramics

Ba0.45Mg0.05Sr0.5-xCaxTiO3 (BMSCT) high entropy ceramics were prepared using a solid-state reaction process sintered at temperatures ranging from 1250 degrees C to 1400 degrees C. A change in Ca content significantly affects the crystalline phase and dielectric properties of the BMSCT ceramics. High resolution TEM observations and the analysis of respective images reveal a large number of intragranular on the nanoscale that are massively disordered and disturbed on the atomic level. The influence of Mg doping, resulting in a shift of the Curie point to-50 degrees C. For Ca-substitution (up to 10 at.%), a broad phase transition is observed in the BMSCT, and the Curie point is-30 degrees C. Comparing the dielectric constant at 1 MHz and 1 GHz, the permittivity of the BMSCT-9182 is only slightly inferior to the on at low frequency-6%, but the one for BST is drastically decreased-70% at microwave frequencies.

Automated summary

Ba0.45Mg0.05Sr0.5-xCaxTiO3 (BMSCT) high entropy ceramics were prepared by a solid-state reaction process sintered at temperatures ranging from 1250 degrees C to 1400 degrees C. The Ca content significantly affected the crystalline phase and dielectric properties of the BMSCT ceramics. High resolution TEM observations showed a large number of intragranular disorder and disturbance on the nanoscale. Mg doping shifted the Curie point to-50 degrees C, while Ca-substitution (up to 10 at.%) led to a broad phase transition and a Curie point of-30 degrees C. Comparing the dielectric constant at 1 MHz and 1 GHz, the permittivity of BMSCT-9182 was slightly lower than that at low frequency (-6%), while for BST it was drastically decreased (-70%) at microwave frequencies.