Interlayer Couplings Mediated by Antiferromagnetic Magnons

Collinear antiferromagnets (AFs) support two degenerate magnon excitations carrying opposite spin polarizations, by which magnons can function as electrons in various spin-related phenomena. In an insulating ferromagnet(F)/AF/F trilayer, we explore the magnon-mediated interlayer coupling by calculating the magnon thermal energy in the AF as a function of the orientations of the Fs. The effect manifests as an interlayer exchange interaction and a perpendicular magnetic anisotropy; they both depend on temperature and the AF thickness. In particular, the exchange interaction turns out to be antiferromagnetic at low temperatures and ferromagnetic at high temperatures, whose magnitude can be $10-100$ $\mu$eV for nanoscale separations, allowing experimental verification.Comment: Physical Review Letters 121, 207202 (2018

Comparison of 2.2mm micro incision and 3.0mm incision coaxial phacoemulsification

AIM:To compare the operation effect of 2.2mm micro incision and 3.0mm incision coaxial phacoemulsification.<p>METHODS: Patients with age-related cataract(90 cases, 90 eyes)were enrolled in the study from January 2012 to June 2013 in our hospital, and they were randomly divided into 2 groups: 2.2mm incision group(45 eyes of 45 cases), 3.0mm incision group(45 eyes of 45 cases). Corneal tunnel incision coaxial phacoemulsification was performed. At 1d, 1wk, 1, 3mo after operation, the visual acuity, corneal endothelial cell count, central corneal thickness, operation astigmatism were recorded.<p>RESULTS: One day after operation, the visual acuity of 2.2mm incision group were significantly improved, the difference was statistically significant(<i>P</i><0.05), there were no differences in two groups at 1wk, 1, 3mo after operation. No significant differences between the two groups of corneal endothelial cell counting, central corneal thickness at 1wk, 1, 3mo after operation were observed(<i>P</i>>0.05). Operation source astigmatism had statistically significant difference at 1d, 1wk, 1, 3mo after operation(<i>P</i><0.05), it decreased significantly in the 2.2mm incision group. <p>CONCLUSION: The 2.2mm small incision coaxial phacoemulsification with postoperative visual acuity improved more significantly, can significantly reduce the operation astigmatism

Bis(μ-4-amino-3,5-dimethyl-4H-1,2,4-triazole-κ 2 N 1:N 2)bis­(dibromidozinc)

The centrosymmetric dimeric title complex, [Zn2Br4(C4H8N4)2], is isotypic with its [Zn2Cl4(C4H8N4)2], [Zn2I4(C4H8N4)2] and [Co2Cl4(C4H8N4)2] analogues. The zinc atom is bonded to two N atoms belonging to triazole bridging rings and to two terminal bromide ligands, in a geometry close to tetra­hedral. Weak N—H⋯Br hydrogen bonds, with the amine functions as donor groups, are observed in the crystal structure, forming a three-dimensional supra­molecular network