Jahn-Teller Inactivity and Magnetic Frustration in GeCo${}_2$O${}_4$ Probed by Ultrasound Velocity Measurements

Tadataka Watanabe, Shigeo Hara, Shin-Ichi Ikeda

Ultrasound velocity measurements of cubic spinel GeCo${}_2$O${}_4$ in single crystal were performed for the investigation of shear and compression moduli. The shear moduli in the param…