Crystal and electronic structure of the room temperature organometallic ferrimagnet V(TCNE)$_2$. Analysis of numerical DoS and magnetic properties as related to orbital and spin-Hamiltonian models

TL;DR

This paper provides a comprehensive analysis of the crystal and electronic structures of the room temperature ferrimagnet V(TCNE)$_2$, combining numerical calculations and magnetic measurements to understand its properties and compare it with similar compounds.

Contribution

It introduces a detailed LSDA+$U$ study and model Hamiltonians to interpret experimental data, offering new insights into the magnetic behavior of V(TCNE)$_2$ and related materials.

Findings

Experimental structure aligns with magnetic data.

Estimated critical temperatures for 2D and 3D regimes.

Explained differences between V(TCNE)$_2$ and Fe(TCNE)$_2$ behaviors.

Abstract

We present a detailed analysis of the results of our numerical study of the crystal and electronic structure of the room temperature organometallic ferrimagnet of general composition V(TCNE)$_{x}$ with $% x\approx 2$. The results of the LSDA+$U$ study show that the experimentally determined structure complies with the magnetic measurements and thus can serve as a prototype structure for the entire family of the M(TCNE)$_{2}$ organometallic magnets. The results of the numerical study and of the magnetic experiments are interpreted using model Hamiltonians proposed here. This allowed us to obtain estimates of the critical temperature in three- and two-dimensional regimes and to give an explanation of the differences in behavior of probably isostructural V(TCNE)$_{2}$ and Fe(TCNE)$_{2}$ species.