Mukhtiyar Singh

Effect of substituting sp-element on half metallic ferromagnetism in NiCrSi Heusler alloy

We present a first principle study of new class of high-Tc half-heusler ferromagnets NiCrZ (Z = Si, P, Ge, As, Te). The structure and magnetic properties are investigated through the calculation of the electronic structure, equilibrium lattice constant, magnetic exchange interaction Jij and Curie temperature Tc. The role of sp-elements and the influence of lattice expansion/compression are also studied. In alloys having 20 valence electrons, a pseudo-gap of the majority band can be formed at Fermi level. Otherwise, the half-metallicity and ferromagnetism at temperatures much higher than room temperature are found to be stable in a wide range of lattice expansion. Based on these results, NiCrZ can be expected to be promising materials for spintronics. ∗Electronic address: divan@cmp.sanken.osaka-u.ac.jp.

First principle prediction of half metallic ferromagnetism in Heusler NiMnZ (Z = P,Ge) compounds

We present first principle calculations of electronic and magnetic properties of NiMnZ (Z = P,Ge) semi Heusler compounds using full potential linearized augmented plane wave (FPLAPW) method based on density functional theory (DFT). To specify the exchange and correlation (XC) effects, the generalized gradient approximation (GGA) is used. The NiMnP compound is predicted to be exactly half metallic ferromagnet (HMF) of type IA with 100% spin polarization at EF whereas NiMnGe show the low value of spin polarization (51%).

Mn-Disorder Effect on Magnetism and Half Metallicity of NiCoMnGa Quaternary Heusler Alloy

The full potential linearized augmented plane wave (FPLAPW) method within generalized gradient approximation (GGA) has been used to investigate the effect of disorder between Ni and Mn atoms on the electronic and magnetic properties of NiCoMnGa quaternary Heusler alloy. We observed that the increase in Mn concentration in NiCoMnGa destroys the half metallicity and decreases the total magnetic moment. Further, the disordered alloy exists in ferrimagnetic (FiM) ground state rather than ferromagnetic (FM) one of ordered system due to antiparallel alignment of extra Mn atom with respect to original Mn atom.

Modified Becke-Johnson Approach for Governing Half Metallic Ferromagnetism in Cr-Doped GaP DMS Compound

The electronic and magnetic properties of Ga1-xCrxP Dilute Magnetic Semiconductor (DMS) compound at doping concentration, x = 0.125 has been calculated using full potential linearized augmented plane wave (FPLAPW) method. The exchange and correlation (XC) effects are taken into account by a semi local, orbital independent modified Becke-Johnson (mBJ) potential as coupled with Local Density Approximation (LDA). Our calculation shows that Cr induces the ferromagnetism in this compound and there is large half metallic (HM) gap appearing in the minority spin channel. We observed that mBJLDA potential enhances the HM gap by ~ 0.25 eV as compared to from its value in Generalized Gradient Approximation (GGA). The improved HM gap can be understood in terms of the mBJLDA-enhanced spin exchange splitting.

High Spin Polarization and Magnetism in NiCrS Heusler Compound

We have investigated magnetic properties of semi Heusler compound NiCrS to search the new candidate showing half‐metallic ferromagnetism (HMF) using full potential linearized augmented plane wave (FPLAPW) method within generalized gradient approximation (GGA) formalism for exchange and correlation effects. We predict that this compound is a nearly half‐metallic (HM) ferromagnet with high degree of spin polarization at Fermi level (EF). The total spin magnetic moment is in good agreement with Slater‐Pauling (SP) rule and is dominated by Cr atom.