Study on optical, dielectric, and magnetic properties of Ba 2 MnGe 2 O 7 ceramics

Ba 2 MnGe 2 O 7 ceramics were prepared by the solid-state reaction method. The prepared powders had a good photon absorption performance in the range of 300–800 nm with the direct band gap energy of 3.1 eV. A dielectric relaxation behavior at low temperature is observed which may come from the dipolar effects associated with the changeable valence of transition metal ions. In addition, antiferromagnetic order was also observed bellow 5.1 K.