Negative tunneling magnetoresistance by canted magnetization in MgO/NiO tunnel barriers

The influence of insertion of an ultra-thin NiO layer between the MgO barrier and ferromagnetic electrode in magnetic tunnel junctions has been investigated by measuring the tunneling magnetoresistance and the X-ray magnetic circular dichroism (XMCD). The magnetoresistance shows a high asymmetry with respect to bias voltage, giving rise to a negative value of -16% at 2.8 K. We attribute this to the formation of non-collinear spin structures in the NiO layer as observed by XMCD. The magnetic moments of the interface Ni atoms tilt from the easy axis due to exchange interaction and the tilting angle decreases with increasing the NiO thickness. The experimental observations are further support by non-collinear spin density functional theory

Tris(ethyl­enediamine)zinc(II) hexa­fluorido­silicate

The title compound, [Zn(C2H8N2)3](SiF6), was synthesized ionothermally using choline chloride–imidazolidone as solvent and template provider. In the crystal structure, the anions and cations are located on special positions of site symmetry 3.2 and show a typical octa­hedral geometry. The ZnII ion is coordinated by six N atoms from three ethyl­enediamine mol­ecules. The crystal structure displays weak hydrogen bonding between [SiF6]2− anions and the ethyl­enediamine NH hydrogen atoms

Tribological properties of fabric self-lubricating liner based on organic montmorillonite (OMMT) reinforced phenolic (PF) nanocomposites as hybrid matrices

Organic montmorillonite (OMMT) reinforced phenolic (PF) nanocomposites with OMMT contents of 2 and 5 wt% were fabricated by the two-step OMMT intercalation process, resulting in the further increase of interlayer spacing of OMMT from 2.07 to 4.27 nm. Prepared OMMT/PF composites were found to possess a mix of intercalated and agglomerated clay structures via X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). Results obtained via differential scanning calorimetry (DSC) and thermogravimetry (TG) revealed that the thermal stability of PF matrices was enhanced by the incorporation of OMMT. With OMMT/PF nanocomposites as hybrid matrices, fabric self-lubricating liners were prepared to evaluate their tribological properties. Effects of OMMT on friction coefficient, wear loss and wear morphology of fabric self-lubricating liner, based on OMMT/PF nanocomposites, were studied via long-term friction and wear tests. Tribological properties of liners with different OMMT contents were investigated by imitating a high-velocity/light-load condition. The addition of OMMT appears to enhance the friction and wear properties of fabric self-lubricating liner, and the preferable OMMT content is around 2 wt%