Plasma-induced magnetic phase in 3D $\mathrm{Mn^{II}-Nb^{IV}}$ octacyanidometalate with magnetic sponge behavior

Autor: Czernia, Dominik, Konieczny, Piotr, Perzanowski, Marcin, Nowicka, Beata, Pinkowicz, Dawid
Rok vydání: 2024
Předmět:
Druh dokumentu: Working Paper
Popis: A new magnetic phase with $T_C = 72 \ \mathrm K$ was obtained by exposing the three-dimensional $\mathrm{\{ [Mn^{II}(H_2O)_2]_2[Nb^{IV}(CN)_8] \cdot 4H_2O \} _n}$ coordination ferrimagnet ($T_C = 49 \ \mathrm K$) to air, oxygen, nitrogen, and argon-based plasma. The X-ray powder diffraction pattern revealed that the unit cell shrank after plasma treatment, leading to a 20% enhancement of the superexchange couplings, as estimated from the mean-field approximation (MFA) model. Although no stable dehydrated form was found in the thermogravimetric analysis, the observed changes are attributed to the removal of crystallization water molecules. The plasma-induced magnetic phase could not be obtained by exposing the studied material to 0% relative humidity during dynamic vapor sorption. Instead, the material underwent a major structural reorganization after dehydration, necessitating an extended MFA model to reproduce the magnetic susceptibility. These findings demonstrate that plasma-induced changes can create unique magnetic phases in molecule-based systems that are otherwise unobtainable.
Comment: 20 pages, 11 figures, 1 table
Databáze: arXiv