Structure refinement and magnetic properties of synthetic Co3Ge2O5(OH)4 phyllogermanate

Belskaya, N.A., Khrapova, E.K., Ivanova, A.A., (...), Pavlov, S.I., Krasilin, A.A.// JMMM//

Co3Ge2O5(OH)4 relates to a specific group of 1:1 layered compounds with an ability to form either platy or tubular particles depending on chemical composition. Despite successful synthesis and perspective application, there is a lack of information on its crystal structure and magnetic properties, granted by Co ions. Co3Ge2O5(OH)4 phyllogermanate nanoparticles have been obtained using a hydrothermal method and characterised using powder X-ray diffraction and magnetisation measurements. Triclinic symmetry with a 1:P1 space group has been established. The unit cell contains three layers perpendicular to the  crystallographic direction, with 7.6 Å spacing and −�/3 shift of the middle layer. At a low magnetic field of 100 Oe the compound undergoes a magnetic transition at �N=5.2 K. The field of 9 T is not sufficient to take the sample to a magnetically saturated state with an asymptotic magnetic moment of 2.43 �B/Co2+. The estimations of the intralayer and interlayer exchange constants give values of �1/�B=2.75 K and �2/�B=0.25 K, respectively.