Transition from ferro- to ferrimagnetic ordering via Mn-disorder in (Ni,Co)MnGa quaternary Heusler alloy

An inclusive investigation of electronic and magnetic properties of ordered and disordered (Ni,Co)MnGa quaternary Heusler alloy has been undertaken using the density functional theory-based full potential linearized augmented plane wave method within generalized gradient approximation as exchange–correlation potentials. We observe that the increasing Mn concentration in Ni_1?x CoMn_1+x Ga (x = 0, 0.25, 0.50 and 0.75) lowers the ferromagnetic (FM) character of the parent (Ni,Co)MnGa alloy. This change creates two inequivalent Mn sites aligning antiparallel to each other and generates the ferrimagnetic (FiM) ordering in all resultant disordered alloys. Further, this replacement sets off a structural change from Y- to X_a-structure. The highest magnetic moment has been found to be 4.95 μ_B for ordered (Ni,Co)MnGa alloy, whereas it decreases with increase in Mn-concentration for disordered systems. The variation of half-metallicity with increasing Mn concentration is analysed. The stability of FM and FiM state for the present ordered and disordered alloys, respectively, is also examined.     

Realizing high thermoelectric performance in p-type RbZn4P3 Zintl compound: a first-principles investigation

Journal of Materials Science - This work presents structural, elastic, electronic, and thermoelectric properties of a tetragonal Zintl compound RbZn4P3, using the Density Functional Theory and...     

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

The investigation of the electronic and magnetic properties of semi Heusler alloy, NiCrSi and alloys obtained by substituting Si with Ge and P (i.e. NiCrGe and NiCrP) has been presented. The present work aims to search the new candidates showing half metallic (HM) ferromagnetism using all-electron full potential linearized augmented plane wave (FPLAPW) method within generalized gradient approximation (GGA) formalism for exchange and correlation (XC) effects. We predict that these alloys are true half metallic ferromagnets (HMFs), showing an indirect band gap in minority density of states (DOS). This gap is largest in case of NiCrSi (0.91 eV). The substitution of sp-element in NiCrSi results in the minority band gap reduction. The main contribution in total magnetic moment comes from Cr-3d states. Moreover, it has an integer value in present alloys as expected in accordance with the Slater-Pauling (SP) rule.