New High-T_cHalf-Heusler Ferromagnets NiMnZ (Z=Si, P, Ge, As)

Abstract

Based on the first principle calculation, we propose a new class of high-Tc half-heusler ferromagnets NiMnZ (Z = Si, P, Ge, As). The structural and magnetic properties are investigated through the calculation of the electronic structure, phase stability, equilibrium lattice constant, magnetic exchange interaction Jij and Curie temperature Tc. It is found that all alloys show half-metallicity and ferromagnetism at temperatures much higher than room temperature in a wide range of lattice expansion (compression). At the equilibrium lattice constant, Tc of 715K, 840K, 875K and 1050K are predicted by Monte Carlo simulation for NiMnP, NiMnAs, NiMnGe and NiMnSi, respectively. Following these results, these alloys are strongly expected to be promising candidates for spintronic applications.PACS numbers:

Computational investigation of half-Heusler compounds for spintronics applications

“…11, we investigated Y = Sc and found three additional semiconductors (NiScP, NiScAs, and NiScSb) with a negative formation energy (listed in Table III but not included in Figs. [10][11][12]. The NiSc(P,As,Sb) com-pounds have lower formation energies than the corresponding CoTi(P,As,Sb) compounds.…”

“…Because they have 100% spin polarization at the Fermi level and can have relatively high Curie temperatures [10,11], Heusler-based half-metals have attracted significant interest for spintronics applications [12][13][14]. Half-metals are considered ideal electrode materials for magnetic tunnel junctions (MTJs) [15], giant magnetoresistance devices (GMRs) [16], and for injecting spinpolarized currents into semiconductors [17].…”

First principle prediction of half-metallic ferromagnetism above room temperature in half-heusler alloys

“…The heusler and halfheusler alloys have attracted great attention because they exhibit an extreme spin polarization [1] and ferromagnetism (FM) at room temperature [1,2,3]. In this paper, based on the first principle calculation of the electronic structure, we investigate the half-metallicity (HM) and FM of half-heusler alloys NiMnZ (Z = Si, Ge, P, As and Sb).…”

Structural and Magnetic Properties of Room Temperature Ferromagnets NiCrZ

“…4 10 Recently, HM ferromagnetism with a very high Curie temperature (T c ) in a new class of halfHeusler alloys NiMnZ has been predicted (particularly, T c ≈ 1050 K for NiMnSi). 15 Also, one can expect that HM ferromagnetism with T c higher than room temperature can be achieved even if Cr replaces Mn in NiMnZ. For example, the first principle calculation of the electronic structure of NiCrZ shows the HM behavior in electronic structures of some alloys NiCrZ with Z = Al, Ga, In, Se and Te.…”