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arXiv · 2402.18195

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

Dominik Czernia·Piotr Konieczny·Marcin Perzanowski·Beata Nowicka·Dawid Pinkowicz
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Abstract

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.

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Dominik Czernia, Piotr Konieczny, Marcin Perzanowski, Beata Nowicka, Dawid Pinkowicz. 2024-02-28. Plasma-induced magnetic phase in 3D $\mathrm{Mn^{II}-Nb^{IV}}$ octacyanidometalate with magnetic sponge behavior. https://arxiv.org/abs/2402.18195

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