Shuailing Ma | Searcharxiv

arXiv2026

Self-induced crystalline fluctuation spin-glass state in Mn7C3 binary compounds

Crystalline spin glasses are attractive compounds owing to their unique nature and applications. Here, we synthesised a bulk Pnma-type Mn7C3 spin glass by a high-temperature, high-pressure method. Experimental characterisation including X-ray diffraction and magnetic susceptibility measurements demonstrated that the compound has a triangular Ising-model-based structure, high freezing temperature of 37.4 K, and novel competition mechanism. Theoretical calculations and simulations revealed that the triangular Mn units are spontaneously frustrated and bridge neighbouring Mn units via polarised C atoms and messenger Mn atoms. Triangular C units each share one electron within a three-pronged electron cloud. This electron is the direct cause of frustration and competition in Mn7C3. The competition within the triangular Mn units suggests that the possible magnetic configurations are highly degenerate and that the Mn7C3 spin glass has high robustness. This work introduces a new family of spin glasses with ordered microgeometries that drive electronic structure disorder, and an application-friendly spin-glass material for use in fields like high-efficiency hardware and algorithm design in artificial intelligence.

cond-mat.mtrl-sci↗

arXiv2025

Constructing a bifunctional platform based on Mn2+-doped Mg2Y8(SiO4)6O2 phosphors for multi-parameter optical thermometry and manometry

Series of the Mn2+-doped Mg2Y8(SiO4)6O2 phosphors were synthesized. Upon excitation at 408 nm, these phosphors exhibited intense orange emission originating from Mn2+, with concentration quenching observed beyond x = 0.07, and they also demonstrated excellent thermal stability. For optical thermometry, two independent parameters, emission band centroid ({\lambda}) and lifetime, were employed as thermal indicators, yielding sensitivities of d{\lambda}/dT = 0.053 nm K-1 and SR = 0.86% K-1, respectively. High-pressure in-situ X-ray diffraction revealed that the phosphors retained structural integrity under compression, accompanied by a progressive lattice contraction. With increasing pressure (0.13-10.89 GPa), a spectral red-shift was observed, corresponding to a pressure sensitivity of d{\lambda}/dp = 4.75 nm GPa-1. Additionally, pressure-dependent shifts in color coordinates allowed the development of a colorimetric manometric response, achieving a relative sensitivity of 3.27% GPa-1. Remarkably, the pressure-induced spectral shift of Mn2+ emission, characterized by low thermal cross-sensitivity, enabled a highly reliable ratiometric manometric strategy, with a relative sensitivity of 72% GPa-1. Notably, the system delivered the highest TIMF reported to date above 3 GPa, peaking at 1940 K GPa-1 at 7 GPa. These results position Mn2+-doped Mg2Y8(SiO4)6O2 phosphors as a highly promising bifunctional material for next-generation, multi-parameter optical sensing applications under extreme conditions.

cond-mat.mtrl-sci↗