Study of structural, electronic, magnetic and vibrational properties of CoFeTiSi quaternary Heusler alloy

We have synthesized CoFeTiSi quaternary Heusler alloy and experimentally measured its structural and magnetic properties. Detailed ab-initio first principle calculations have been performed to investigate the half-metallic behavior of this quaternary Heusler alloy and the effect of disorder on its half-metallicity. The saturation magnetization and Curie temperature are obtained as 1.243 μB/f.u. and 583 K respectively. The spinwave-stiffness constant (D = 3.259 nm2-meV) is obtained from temperature dependence according to Bloch's law. Dynamical stability of the alloy is confirmed from the phonon dispersion curve of the alloy. The first principle calculations show that the alloy is 100% spin-polarized at the Fermi level and the spin-polarization is resistant to the uniform lattice distortion up to a large extent. The effect of anti-site disorder of atoms on the total magnetic moment and the electronic structure is also explored and the moment (and the half-metallicity) is found to be nearly independent (resistant) for the disorders due to Co–Fe and Ti–Si atomic swaps whereas it is affected in case of Co–Si and Fe–Ti atomic swaps. This study reveals that the alloy may be a viable candidate for spintronic applications at room temperature. •Experimental structural and magnetic properties of CoFeTiSi HA is reported for the 1st time.•The measured a, Ms and D is found to be 5.74 Å, 1.24 μB/f.u. and 3.25 nm2-meV respectively.•Detailed theoretical calculations confirm the half-metallicity of the alloy.•Effect of lattice strain and atomic site-disorder on the electronic properties is computed.•Dynamical stability of the alloy is confirmed by studying the PDC and Phonon DOS.