Electronic structure calculation of the structural and magnetic properties of the MgFe2O4. From bulk to surface

H. H. MEDINA CHANDUVI; A. V. GIL REBAZA; A. M MUDARRA NAVARRO; L. A. ERRICO

La Plata

Workshop; X Workshop on Novel Methods for Electronic Structure Calculations; 2023

Spinel ferrites of AFe2O4 (A = Ni, Cu, Mn, Mg, Coor Zn, etc.) have remained one of the most interesting functional materials inrecent decades, because of their unparalleled magnetic, electric and dielectricproperties. These electrical and magnetic properties have a widerange of applications in high and very high frequency radio frequency circuits,transformer cores, data storage devices, high read/write speed, among others.Among different spinel ferrites, magnesium ferrite (MgFe2O4),a soft magnetic n-type semiconducting material possessing inverse spinelstructure is one of the most prominent. In this work, an ab initio study of thestructural, electronic, magnetic and hyperfine properties of MgFe2O4was carried out within the framework of Density Functional Theory(DFT) using the FP-LAPW+LO and Pseudopotential methods, employing theGeneralized Gradient Approximation (GGA) and the GGA+U for the potential termand exchange. The calculations show that the equilibrium structure correspondsto an inverted and antiferromagnetic configuration, in which the magneticmoments of the Fe atoms in the A sites are ordered ferromagnetically with eachother and antiferromagnetically with respect to the Fe in the sub-network of Bsites, while the Magnesium atoms do not polarize.The excellent agreement between theoretical calculations andexperimental results reported in the literature supports the cationdistribution and the lowest energy magnetic configuration obtained for MgFe2O4.From these results, the stability of the different surfaces of this ferritebegan to be studied considering different surface finishes, taking into accountstructural reconstructions in all cases. The results we present predict thatthe most stable surface is inverted, exposing Fe, Mg, and O atoms. This surfacepresents a net magnetic moment, giving rise to a ferrimagnetic system.