Mixed spin S=1 and S=1/2 layered lattice in Cu$_2$F$_5$

TL;DR

This paper investigates the electronic and magnetic properties of Cu$_2$F$_5$, revealing a stable antiferromagnetic order with unusual 2D magnetism due to strong in-plane exchange interactions between mixed spin states.

Contribution

It provides the first detailed DFT+U analysis of Cu$_2$F$_5$, highlighting its unique 2D magnetic behavior with strong anisotropic exchange interactions between S=1 and S=1/2 copper ions.

Findings

Stable antiferromagnetic ordering in Cu$_2$F$_5$

Strong in-plane exchange interactions between mixed spin states

Weak interplane magnetic interactions

Abstract

The electronic and magnetic structure, including the Heisenberg model exchange interaction parameters, was explored for the recently proposed novel cuprate Cu$_2$F$_5$. Using the DFT+U calculation, it is shown that the compound is formed by two types of copper ions with $d^9$ and $d^8$ electronic configurations. We have found a very stable antiferromagnetic ordering with strong anisotropy of exchange interaction that results in the appearance of an unusual 2D-magnetism: within the (100)-plane the exchange between the S=1 and S=1/2 Cu ions has almost the same strength as between the two S=1 ions. The interplane magnetic interaction is five times weaker than the in-plane one.