Search

• Multi-dimensional Ni@C-CoNi with 0D CoNi alloy and 1D Ni@C were synthesized. • The multi-layer heterogeneous interfaces trigger strong interfacial polarization. • Inner 1D Ni interacts with outer 0D CoNi alloy to induce magnetic coupling. • An optimal R L value of -51.4 dB and bandwidth of 4.6 GHz were achieved. Dielectric-magnetic integrated absorbers have attracted arousing attention in microwave absorption, however, it still remains a great challenge to simultaneously achieve superior dielectric polarization and strong magnetic loss. Herein, we propose a multi-scale structure optimization strategy to anchor CoNi-MOFs derived 0D CoNi alloy onto 1D core-shell Ni@C surface. By decorating with the poly-dopamine layer, the connection between 1D NiO and CoNi-MOFs precursors was greatly improved via the electrostatic interaction. Benefiting from the overlapping conductive networks, enhanced interfacial polarization among the multi-dimensional heterogeneous interfaces and strong magnetic interaction, the fabricated multi-dimensional Ni@C-CoNi composites exhibit outstanding microwave absorption. Typically, the optimal reflection loss is as high as –51.4 dB at 1.9 mm, and the effective absorption bandwidth achieves 4.6 GHz with a thickness of only 1.3 mm. This multi-scale structure optimization strategy inspires us with an efficient method to fabricate ideal microwave absorbers and the obtained multi-dimensional composites can be used as promising candidates in electromagnetic radiation protection. [ABSTRACT FROM AUTHOR]

The negative thermal expansion (NTE) properties of the antiperovskite manganese nitrides with micron-scale, submicron-scale and nanometer-scale microstructures, respectively, were investigated using the Mn 3 Cu 0.5 Ge 0.5 N composition as an example. It was discovered that the NTE start temperature, NTE operation temperature range and coefficient of NTE change obviously in a wide range with decreasing the grain size level of the microstructure. The mechanisms for the broadening of the NTE operation temperature range and the decrease in the absolute value of NTE coefficient were proposed based on the grain-size-dependence of the frustrated magnetic interactions and magnetic ordering. The present study indicates that the NTE properties of the antiperovskite manganese nitrides can be tailored by the control of the microstructure scale. [ABSTRACT FROM AUTHOR]

We describe our newly-developed open-source software, named by J x , to perform magnetic force linear response calculations. J x is a user-friendly and efficient tool to calculate magnetic interaction in solids and molecules. Without supercell calculation, it computes both short- and long-range interactions. It is also possible to calculate an orbital-resolved matrix form of magnetic couplings. Functionality and formalism are presented with examples. The program architecture and parallel algorithm are also described. Program Title: Jx Program Files doi: http://dx.doi.org/10.17632/kg5x95gwgj.1 Licensing provisions: LGPL Programming language: Julia Nature of problem: The first-principles estimation of magnetic interaction in solids and molecules. Solution method: Calculate the magnetic coupling constant based on magnetic force response theory. [ABSTRACT FROM AUTHOR]