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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Estimates of the exchange interaction parameter (J) between electronicmagnetic momenta residing in the d-shells of several divalent first rowtransition metal ions, and those residing on the [TCNE]$^-$. anion-radicals(TCNE = tetracyanoethylene) that are bonded to the metal ion are obtained bythe use of the EHCF method in the cluster approximation. The clusters geometrywas set according to that observed for Mn$^{II}$(TCNE)$_{1/2}$(I$_3$)$_{1/2}$and M$^{II}$(TCNE)(C$_4$(CN)$_8$)$_{1/2}$ (M = Fe, Mn) with the [TCNE]$^{-.}$.For the Mn$^{II}$(TCNE)$_{1/2}$(I$_3$)$_{1/2}$ two cluster types areconsidered: one with the geometry corresponding to [TCNE]$^{-.}$ in thetwo-dimensional layer, and another connecting the layers. ForM$^{II}$(TCNE)(C$_4$(CN)$_8$)$_{1/2}$ only the layer position of the[TCNE]$^{-.}$ is considered. In all cases the LUMO (singly filled in thematerial) is predominantly concentrated on the ethylenic C-C bond and isantibonding. The J value for the Mn$^{II}$(TCNE)$_{1/2}$(I$_3$)$_{1/2}$ layeris at least as twice as strong as one for the similar geometry forM$^{II}$(TCNE)(C$_4$(CN)$_8$)$_{1/2}$. The correct order of magnitude of thecalculated exchange parameters, as compared with those extracted fromexperimentsindicates the general validity of this approach. However, the directcomparison of these J values with the critical temperatures is not possiblesince these latter heavily depend on details of the interlayer coupling notavailable through the EHCF procedure. In order to get more information on thegeometry dependence of the exchange parameters, the dependence on the tiltangle of the TCNE with respect to the plane formed by the metal ions and fourequatorial NCMe groups was investigated. In all cases, a remarkably strongdependence, having different trends depending on the number of electrons in thed-shells of respective transition metal ions was observed.

Exchange Parameters in the TCNE-based Magnets as Estimated with use of the Effective Hamiltonian Crystal Field Method