arXiv subjects

A. Birsan

Publications and source records attributed to A. Birsan.

6 recordsLinked to original sources

arXiv2015

First principle investigations of the structural, electronic and magnetic properties of the new zirconium based full-Heusler compounds, Zr2MnZ (Z = Al, Ga and In)

The crystal structure, electronic and magnetic properties of the new full-Heusler compounds Zr2MnZ (Z=Al, Ga, In), were studied within the Density Functional Theory (DFT) framework. The materials exhibit unique properties that connect the spin gapless semiconducting character with the completely compensated ferrimagnetism. In magnetic configurations, Zr2MnZ (Z=Al, Ga, In) crystallize in inverse Heusler structure, are stable against decomposition and have zero magnetic moment per formula unit properties, in agreement with Slater-Pauling rule. The Zr2MnAl compound presents spin gapless semiconducting properties with a energy band gap of 0.41 eV in the majority spin channel and a zero band gap in the minority spin channel. By substituting Ga or In elements, for Al in Zr2MnAl, semiconducting pseudo band gaps are formed in the majority spin channels due to the different neighborhood around the manganese atoms, which decreases the energy of Mn's triple degenerated anti-bonding states.

cond-mat.mtrl-sci↗

arXiv2014

Theoretical investigations of electronic structure and magnetism in Zr2CoSn full-Heusler compound

The half-metallic properties of a new and promising full-Heusler compound, Zr2CoSn, are investigated by means of ab initio calculations within the Density Functional Theory framework. The ferromagnetic ordered Hg2CuTi-type crystal structure is energetically favorable and the optimized lattice parameter is 6.76 A. The total magnetic moment calculated is 3 uB/f.u. and follows a typical Slater-Pauling dependence. The half metallicity disappears if the unit cell volume is contracted by 5 %.

cond-mat.mtrl-sci↗

arXiv2014

Electronic structure and magnetism of new scandium-based full Heusler compounds: Sc2CoZ (Z=Si, Ge, Sn)

First principles FPLAPWcalculations were performed in the framework of Density Functional Theory (DFT), to study the electronic structures and magnetic properties for the new full-Heusler compounds: Sc2CoZ (Z=Si, Ge, Sn). The investigated materials are stable against decomposition, in ferromagnetic configuration and crystallize in the inverse Heusler structures. The half-metallic properties as function of the variation of unit cell volumes are analysed regarding the fourth main group constituent elements. The electronic structure calculations for Sc2CoSi and Sc2CoSn show half-metallic characters, with indirect band gaps of 0.544 eV and 0.408 eV at optimized lattice parameters of 6.28 A and 6.62 A, respectively. For Sc2CoGe compound, the Fermi energy is not pinned inside the energy band gap from minority density of states, neither for unit cell contraction or for enlargement. The calculated total magnetic moments are 1muB/f.u., for all compounds, in agreement with Slater-Pauling rule.

cond-mat.mtrl-sci↗

arXiv2013

Band structure calculations of Ti\raisebox{-.2ex}{\scriptsize 2}FeSn: a new half-metallic compound

Within the framework of density functional theory, the electronic structure and magnetic properties have been studied for the Ti\raisebox{-.2ex}{\scriptsize 2}FeSn full-Heusler compound. The ferromagnetic state is found to be energetically more favorable than paramagnetic and antiferromagnetic states. The spin-polarized results show that Ti\raisebox{-.2ex}{\scriptsize 2}FeSn compound has half-metallic ferromagnetic character with a total spin moment of $2 μ_{B}$ and a band gap in the minority spin channel of 0.489 eV, at the equilibrium lattice constant a=6.342 A.

cond-mat.mtrl-sci↗

arXiv2013

Prediction of half metallic properties in Ti\raisebox{-.2ex}{\scriptsize 2}CoSi Heusler alloy based on density functional theory

The electronic and magnetic properties of Ti\raisebox{-.2ex}{\scriptsize 2}CoSi Heusler compound are investigated using density functional calculations. The optimized lattice constant is found to be 6.030 A. The compound is a half-metallic ferromagnet with an energy gap in minority spin channel of 0.652 eV at equilibrium lattice constant, which leads to a 100% spin-polarization. The obtained total magnetic moment from spin-polarized calculations is 3.0 $μ_{B}$ for values of lattice constants higher than 5.941 A. The half-metallicity is spoiled for a compressed volume of 4%, suggesting a possible application as pressure sensitive material.

cond-mat.mtrl-sci↗

arXiv2013

Half metallic state and magnetic properties versus the lattice constant in Ti\raisebox{-.2ex}{\scriptsize 2}CoSn Heusler compound: an ab initio study

The half metallic properties of Ti\raisebox{-.2ex}{\scriptsize 2}CoSn full-Heusler compound is studied within the framework of the density functional theory with the Perdew Burke Ernzerhof generalized gradient approximation (GGA). Structural optimization was performed and the calculated equilibrium lattice constant is 6.340 A. The spin up band of compound has metallic character and spin down band is semiconducting with an indirect gap of 0.598 eV at equilibrium lattice constant. For the lattice parameter, ranging from 6.193 to 6.884 A the compound presents 100% spin polarization and a total magnetic moment of 3$μ_{B}$.

cond-mat.mtrl-sci↗