Relaxor Nature and Energy Storage Properties of Sr2–xMxNaNb5–xTixO15 (M = La3+ and Ho3+) Tungsten Bronze Ceramics

A series of lead- and bismuth-free tetragonal tungsten bronze ceramics with chemical formula given as Sr2–xMxNaNb5–xTixO15 (M = La3+ and Ho3+) were prepared. Through codoping of A- and B-sites, swi...