Experimental And Theoretical Study Of Heusler Alloy Mn₂V_1-xCo_xAl

An active field of magnetoelectronics or spin electronics has intensified research on the so-called Heusler compound materials,which can be a promising class of materials combining physical properties like higher spin polarization or higher Curie temperature,and such properties can be adjusted definitely.A substantial cause to promote the potential applications in spin-based electronics is the half-metallic Heusler compounds have been predicted to exhibit 100%spin polarization at the Fermi level,And the available studies indicate that the spin transfer mechanism of low magnetic moment compound proceeds efficiently,as the reversal of magnetic state can be easy to implement with a small spin-polarized current via the transfer of angular momentum between the local magnetic moments and the conduction spins.We try to find a suitable way to obtain a Heusler half-metallic compound with controllable properties,like high spin polarization,controllable magnetization and high Curie temperature.In this paper we present the theoretical identification and the experimental characterization results to study the structure,half-metallic,magnetization and electronic transport properties.The main research and results are as follows:1.The structural,magnetic,electronic and transport properties of Mn2V1-x Cox Al alloys have been studied theoretically,our first-principles results have prefiguratively indicate that the substitution of Co atoms for V sites can be controllable to decrease the magnetic moment.And the alloy has 100%spin polarization and zero net magnetic moment when x=0.5,as well as the moments of atoms are compensated.2.Experimentally,we use the vacuum arc furnace to prepare the Mn2V1-x Cox Al alloys,the samples are then measured after optimized heat treatment process.we outline the main results to reveal the structure,half-metallic,magnetization and changes in the electronic properties.As a result,the exclusive heat treatment for different Mn₂V_1-xCo_xAl alloy in stoichiometry can affect the crystalline structure distinctly.Specially,we can definitely gain the alloy with considerable L2₁structure since we set exclusive annealing temperature for specific Co-containing one.3.our first-principles computations have prefiguratively indicate that the Co_2-xMn_xCr Al alloys,with a tendency to substitute Co sites by Mn atoms,can be conductive to gradually stable the magnetic moments of the Co_2-xMn_xCr Al Heusler compounds,and in all considered cases we have a half-metallic ferrimagnetic state with the completely spin polarization for Mn-containing quaternary compounds.CoMnCr Al compound exhibits the most positive energy difference theoretically,and the bulk samples mainly contains the crystals with B2 structure?...