English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Materials with negative thermal expansion (NTE), which contract upon heating,are of great interest both technically and fundamentally. Here, we report giantNTE covering room temperature in mechanically milled antiperovksite GaNxMn3compounds. The micrograin GaNxMn3 exhibits a large volume contraction at theantiferromagnetic (AFM) to paramagnetic (PM) (AFM-PM) transition within atemperature window ({\Delta}T) of only a few kelvins. The grain size reduces to~ 30 nm after slight milling, while {\Delta}T is broadened to 50K. Thecorresponding coefficient of linear thermal expansion ({\alpha}) reaches ~ -70ppm/K, which is almost two times larger than those obtained in chemically dopedantiperovskite compounds. Further reducing grain size to ~ 10 nm, {\Delta}Texceeds 100 K and {\alpha} remains as large as -30 ppm/K (-21 ppm/K) for x =1.0 (x = 0.9). Excess atomic displacements together with the reduced structuralcoherence, revealed by high-energy X-ray pair distribution functions, aresuggested to delay the AFM-PM transition. By controlling the grain size viamechanically alloying or grinding, giant NTE may also be achievable in othermaterials with large lattice contraction due to electronic or magnetic phasetransitions.

Giant negative thermal expansion covering room temperature in nanocrystalline GaNxMn3