Publications by authors named "N-Diaye Adama"

Materials science exploits only properties that are available at ambience. Therefore, although high-pressure changes the physical state of all condensed matter, most of the extraordinary properties discovered vanish after decompression and cannot be utilized. Here, we demonstrate sublattice decoupling in a mixed-anion chalcohalide RbReSI upon compression, in which the [RbI] framework is soft and plastic, while the [ReSI] clusters are hard and elastic.

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The magnetic properties of a series of trimetallic (Co,Ni)Fe Prussian blue analogues (PBAs) were investigated by SQUID magnetometry and X-ray magnetic circular dichroism (XMCD) at the three transition metal (TM) K-edges. In turn, the PBA trimetallic series was used as a tool in order to better understand the information contained in TM K-edge XMCD and particularly the chemical nature of the probed species (extended sub-lattice or localized entities). The results show that the magnetic behavior of the compounds is dictated by competing exchange interactions between the Co-Fe and Ni-Fe pairs, without spin frustration.

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To disentangle the information contained in transition-metal K-edge X-ray magnetic circular dichroism (XMCD), two series of Prussian blue analogs (PBAs) were investigated as model compounds. The number of 3d electrons and the magnetic orbitals have been varied on both sites of the bimetallic cyanide polymer by combining with the hexacyanoferrate or the hexacyanochromate entities' various divalent metal ions A (Mn, Fe, Co, Ni, and Cu). These PBA were studied by Fe and Cr X-ray absorption spectroscopy and XMCD.

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Two series of Prussian blue analogs (PBA) were used as model compounds in order to disentangle the information contained in X-ray magnetic circular dichroism (XMCD) at the K-edges of transition metals. The number of 3d electrons on one site of the bimetallic cyanide polymer has been varied by associating to the [Fe(CN)] or the [Cr(CN)] precursors various divalent metal ions A (Mn, Fe, Co, Ni, and Cu). The compounds were studied by X-ray diffraction and SQUID magnetometry, as well as by X-ray absorption spectroscopy and XMCD at the K-edges of the A transition metal ion.

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In order to disentangle the physical effects at the origin of transition metal K-edge X-ray magnetic circular dichroism (XMCD) in coordination polymers and quantify small structural distortions from the intensity of these signals, a systematic investigation of Prussian blue analogs as model compounds is being conducted. Here the effects of the temperature and of the external magnetic field are tackled; none of these external parameters modify the shape of the XMCD signal but they both critically modify its intensity. The optimized experimental conditions, as well as a reliable and robust normalization procedure, could thus be determined for the study of the intrinsic parameters.

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