Structural, Electronic and Magnetic Properties of Geometrically Frustrated Spinel CdCr2O4 from First-principles Based on Density Functional Theory

Bolandhemat N

doi:10.4172/2169-0022.1000250

Abstract

First-principles calculations are used to investigate the structural, electronic, and magnetic properties of CdCr2O4 with magnetic Cr cations, focusing on the changes through the magnetic phase transitions which shows relief of the geometric frustration of the ferromagnetic and antiferromagnetic orderings on the pyrochlore lattice. We computed the structural and electronic properties for the paramagnetic, ferromagnetic and antiferromagnetic orderings in cubic ( F 3 dm) and tetragonal (I41 ⁄amd) structures of CdCr2O4. We optimized the crystal structures with the PM, FM and AFM orderings using a pseudopotential plane wave (PP-PW) method within the generalized gradient approximation (GGA), and computed the electronic properties to investigate the magnetic properties in the geometrically frustrated ferromagnetic and antiferromagnetic spinel CdCr2O4 based on density functional theory and understanding of the principles of Quantum ESPRESSO in magnetic materials. On the other hand, the effect of magnetism were obtained and analyzed on the basis of density of states (DOS), projected density of states (PDOS), and charge density distribution.

Highlights

Spinels are a captivating class of materials that indicate rich complex behavior and novel ground states such as large magnetoresistance effects [1], non-collinear spin configurations [2], magnetodielectric coupling [3], and spin liquid states [4]
Spinel CdCr2O4 with the Cd non-magnetic and the Cr magnetic ions span a huge range of magnetic exchange strengths and different magnetic ground states
We discuss about the computational results on LSDA calculations for both cubic and tetragonal structures of geometrically frustrated spinel CdCr2O4 in different magnetic configurations

Summary

Introduction

Spinels are a captivating class of materials that indicate rich complex behavior and novel ground states such as large magnetoresistance effects [1], non-collinear spin configurations [2], magnetodielectric coupling [3], and spin liquid states [4]. Spinel is the magnesium aluminum oxide member of this large group of materials with the Mg2+Al3+2O2-4 formula that gives its name to the family of compounds that are identified by two cation sites: an octahedral site and a tetrahedral site [5]. It is named as spinel to any material that have the general formula A2+[B3+]2[X2−]4 which crystallizes in the facecentered cubic crystal system and are described by the space group Fd3̅̅m (No 227). In this structure, the X anions are located in a cubic close packed lattice, the cations A occupy tetrahedral (1/8, 1/8, 1/8).

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Conclusion