Eur. Phys. J. B 61, 131-139 (2008)
https://doi.org/10.1140/epjb/e2008-00063-7

First principles study of structural, magnetic and electronic properties of half-metallic CrO₂ under pressure

¹ Department of Physics, Barkatullah University, Bhopal, 462026, India
² Department of Physics, Anna University, Chennai, 600 025, India

Corresponding author: ^a mraja1948@yahoo.co.in

Received: 29 August 2007
Revised: 28 November 2007
Published online: 16 February 2008

Abstract

A first-principles tight-binding linear muffin tin orbital (TB-LMTO) method within the local-density approximation is used to calculate the total energy, lattice parameter, bulk modulus, magnetic moment, density of states and energy band structures of half-metallic CrO₂ at ambient as well as at high pressure. The magnetic and structural stabilities are determined from the total energy calculations. From the present study we predict a magnetic transition from ferromagnetic (FM) state to a non-magnetic (NM) state at 65 GPa, which is of second order in nature. We also observe from our calculations that CrO₂ is more stable in tetragonal phase (rutile-type) at ambient conditions and undergoes a transition to an orthorhombic structure (CaCl₂-type) at 9.6 GPa, which is in good agreement with the experimental results. We predict a second structural phase transition from CaCl₂- to fluorite-type structure at 89.6 GPa with a volume collapse of 7.3%, which is yet to be confirmed experimentally. Interestingly, CrO₂ shows half metallicity under ambient conditions. After the first structural phase transition from tetragonal to orthorhombic, half metallicity has been retained in CrO₂ and it vanishes at a pressure of 41.6 GPa. Ferromagnetism is quenched at a pressure of 65 GPa.