Phase stability, mechanical, electronic, magnetic and thermodynamic properties of the Pd2PrX(X=Cl, F) compounds: An Ab-initio study

Many of the known examples of half-metallic ferromagnets HMF are oxides, sulfides, or Heusler alloys have attracted some interest for their potential use in spintronics. In order to achieve such understanding we have performed an ab-initio calculations with spin polarization using plane-wave pseudo potential technique based on the density-functional theory (DFT), the exchange-correlation potential was treated with the generalized gradient approximation (PBE-GGA), whereas for the treatment of on-site electron-electron correlations the PBE-GGA+U approximation (where U is the Hubbard Coulomb energy term) are applied for the calculation of the structural, electronic, elastic and magnetic properties of Pd2PrX (X=Cl, F). The results showed that for Pd2PrCl and Pd2PrF, Hg2CuTi-type structure is energetically more stable than Cu2MnAl-type structure at the equilibrium volume. Electronically, Pd2PrCl and Pd2PrF exhibit half-metallicity with small band gaps of 0.06 and 0.25eV respectively with GGA-PBE+U in the spin-down channels whereas spin-up channels are conducting. The calculated total magnetic moment of 2.00 μB per formula unit is very close to integer value and agree well with the Slater-Pauling rules ( Mtot=34-Ztot), where the magnetic moment is basically carried by Pr atoms. However, the elastic properties show that Pd2PrX (X=Cl, F) compounds are ductile and anisotropic according to the analysis of B/G and Cauchy’s pressure. The Thermodynamic properties were also analyzed using the quasi-harmonic Debye model. Both the compounds are found structurally stable.