Electronic Structure of Fe2-xCoxVAl Heusler Alloy: A
Ground State Calculation by GGA
Vivek Kumar Jain1, Vishal Jain1, Sijo A K1, N. Lakshmi1*, K. Venugopalan1
1
Department of Physics ,Mohanlal Sukhadia University, Udaipur-313001, Rajasthan, India
*
Corresponding author’s e-mail:nambakkat@yahoo.co.in, Tel.: +91-9928093213
Abstract
The effects of Co substitution at Fe site on electronic
structure of Fe2-xCoxVAl Heusler alloy has been studied by
using GGA exchange correlation potentials. It is found
that the semi metallic behavior of Fe2VAl reduces while
half-metallicity is induced with high spin polarization,
lattice parameter and total magnetic moment enhanced.
Keywords: Heusler alloy, Half- metallic, Semi metallic,
Magnetic moment, Electronic Structure calculation.
the Slater-Pauling curve as well as experimental values.
The moment for FeCoVAl is 1µB, and is 2µB for
Co2VAl. Al magnetic moment is almost zero has
negligible contribution to the total moment. Co moment
increases with increase in the x value. Fe moment
increases till x=1 and decreases thereafter. This study
thus shows that substitution of Fe with Co retains the
half-metallic characteristic of Fe2VAl while increasing
the magnetic moment.
Introduction
Theoretical and experimental investigation of
Fe2VAl shows semi metallic behavior and has been
extensively studied due to the structural, thermoelectric,
elastic and transport applications [1-2] but has poor
magnetic properties which are expected to improve on
Co substitution. The change in electronic and
corresponding magnetic properties on Co substitution
for Fe are studied in this paper.
Results and Discussion
GGA approximation was used for electronic
structure calculations using WIEN2k package. L21
ordered Fe2Val was used for calculation. In this work,
Fe atom is replaced with Co atom (Fe2-xCoxVal, x = 0 to
2). Reported experiment lattice parameter was used to
find out the equilibrium lattice constant by Muranghan
equation of state. The lattice parameter increases and
bulk modulus decreases as Co concentration increases.
Detailed analysis shows drastic changes of DOS in the
vicinity of the Fermi level on going from Fe2VAl to
Co2VAl. In the case of Fe2VAl, the Fermi level appears
to be in the pseudo gap both for spin up and down DOS
and shows semi metallic behavior. Spin polarization
(SP) for Fe2VAl is negligible and increases as x
increases reaching ~100% for (x>1) and shows halfmetallic behavior because the up spin exhibits a metallic
electronic structure while in down spins electrons are
semiconducting with small band gap. The moment for
Fe2VAl is zero because the interaction between d
electrons of Fe and V are in opposite directions and
cancel the overall moment. Our calculations of moment
for Fe2-xCoxVAl show that it is systematic and matches
Fig. 1: Total DOS of Fe2VAl, FeCoVAl and Co2VAl
Acknowledgment
The work has been supported by UGC-DSA,
DST-FIST schemes of the Department of Physics, M L
Sukhadia University, Udaipur.
References
[1] Bin Xu, Xingfu Li, Gongqi Yu, Jing Zhang,
Shanshan Ma, Yusheng Wang, Lin Yi, “The structural,
elastic and thermoelectric properties of Fe2VAl at
pressures”, Journal of Alloys and Compounds, 565,
(2013), pp. 22-28.
[2] Yoichi Nishino, “Unusual electron transport in
Heusler-type Fe2VAl compound,” Intermetallics, 8
(2000) 1233-1241.