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//

https://doi.org/10.1016/j.jmmm.2023.171262

Co $_{3}$ Ge $_{2}$ O $_{5}$ (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. Co $_{3}$ Ge $_{2}$ O $_{5}$ (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 $c$ crystallographic direction, with 7.6 Å spacing and $- b / 3$ shift of the middle layer. At a low magnetic field of 100 Oe the compound undergoes a magnetic transition at $T_{N} = 5.2$ 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 $μ_{B} /$ Co $^{2 +}$ . The estimations of the intralayer and interlayer exchange constants give values of $J_{1} / k_{B} = 2.75$ K and $J_{2} / k_{B} = 0.25$ K, respectively.