We combined Raman scattering and magnetic susceptibility to explore the properties of [(CH₃)₂NH₂]Mn(HCOO)₃ under compression. Analysis of the formate bending mode reveals a broad two-phase region surrounding the 4.2 GPa critical pressure that becomes increasingly sluggish below the order–disorder transition due to the extensive hydrogen-bonding network. Although the paraelectric and ferroelectric phases have different space groups at ambient-pressure conditions, they both drive toward P1 symmetry under compression. This is a direct consequence of how the order–disorder transition changes under pressure. We bring these findings together with prior magnetization work to create a pressure–temperature–magnetic field phase diagram, unveiling entanglement, competition, and a progression of symmetry-breaking effects that underlie functionality in this molecule-based multiferroic. That the high-pressure P1 phase is a subgroup of the ferroelectric Cc suggests the possibility of enhanced electric polarization as well as opportunity for strain control.

中文翻译：

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开发多铁性[（CH3）2NH2] Mn（HCOO）3的压力-温度-磁场相图。

我们结合拉曼散射和磁化率来探索[（CH ₃）₂ NH ₂ ] Mn（HCOO）₃在压缩下的性质。对甲酸弯曲模式的分析显示出，在4.2 GPa临界压力附近有一个宽广的两相区域，由于广泛的氢键网络，在有序-无序过渡以下，该两相区域变得越来越缓慢。尽管顺电和铁电相在环境压力条件下具有不同的空间群，但它们都朝着P1个对称受压。这是有序-无序过渡在压力下如何变化的直接结果。我们将这些发现与先前的磁化工作结合起来，创建了压力-温度-磁场相图，揭示了纠缠，竞争以及对称破坏效应的进展，这些破坏作用是基于分子的多铁性化合物的功能基础。高压P 1相是铁电Cc的一个子集，表明增强极化的可能性以及应变控制的机会。