Preparation and characterization of Z-type hexaferrites, Ba3(1- x )Sr3 x Co2Fe24O41 with x = 0–0.5, via a two-step calcination with an intermediate wet milling - Aoyama, M.; Jadambaa, Temuujin; Senna, M.; Masuko, T.; Ando, C.; Kishi, H. (Springer New York, 2006)