Effects of Ga substitution on the structural and magnetic properties of half metallic Fe2MnSi Heusler compound

Abstract

The so-called half-metallic magnets have been proposed as good candidates for spintronic applications due to the feature of exhibiting a hundred percent spin polarization at the Fermi level. Such materials follow the Slater-Pauling rule, which relates the magnetic moment with the valence electrons in the system. In this paper, we study the bulk polycrystalline half-metallic Fe2MnSi Heusler compound replacing Si by Ga to determine how the Ga addition changes the magnetic, the structural, and the half-metal properties of this compound. The material does not follow the Slater-Pauling rule, probably due to a minor structural disorder degree in the system, but a linear dependence on the magnetic transition temperature with the valence electron number points to the half-metallic behavior of this compound.

Influence of Preparation Technology on Microstructural and Magnetic Properties of Fe2MnSi and Fe2MnAl Heusler Alloys

“…Independently on the Curie-Weiss law, the Curie temperature was also determined from the ZFC-FC curves ( Figure 5 ) using one tangent and/or two tangent method [ 32 ]. This resulted in T C ~216 K for the DS sample in good agreement with the values presented in Table 4 and comparable with 220 K presented for ingot-type samples, e.g., in Reference [ 33 ]. The Curie temperature of the RS sample determined by the tangent methods was about 22 K lower compared to that in Table 4 .…”

Experimental evidences of enhanced magnetocaloric properties at room temperature and half-metallicity on Fe 2 MnSi-based Heusler alloys

“…More precisely, the tunnel magnetoresistance ratio (TMR) become theoretically infinity based on the Julliere's model, for tunnel junctions using half-metals in both electrodes [31]. The half-metallicity can be verified from either the theoretical density of states, obtained from first-principle methods, or the total magnetic moment of the compound, that must obey the generalized Slater-Pauling rule M = (N v − 24)µ B [2], where the valence electrons number N v is written, for our case, as [12]:…”

“…The magnetic and structural properties of parent Fe 2 MnSi and Fe 2 MnGa Heusler alloys have been previously investigated [33][34][35]. The former is a well know half-metallic ferromagnet alloy with T c around 224 K [12] and F m3m spacial group (Cu 2 MnAl type structure); while Fe 2 MnGa is also a half-metallic ferromagnet with T c far above room temperature, around 800 K as previously reported [35,36], and crystallizes in the P m3m spacial group (Cu 3 Au type structure).…”

“…Other important example is the half-metallicity, in which the alloy presents a gap in the minority band, working therefore as a perfect spin filter, since electrons at the Fermi level are fully polarized. This feature is useful for spintronic purposes and is found, for instance, on Fe 2 MnSi [12], Fe 2 MnP [13] and the high temperature ferromagnets Co 2 MnSi and Co 2 MnGa [2]. The aim of this work is thus to predict a multifunctional Heusler alloy, with enhanced magnetocaloric effect at room temperature and half-metallicity.…”

Phase composition and growth mechanisms of half-metal Heusler alloy produced by Pulsed Laser Deposition: From core-shell nanoparticles to amorphous randomic clusters

“…To this purpose, the material must have the highest magnetic saturation moment and Curie temperature as possible; as well as follow the SlaterPauling rule and, in addition, be ferromagnetic. Fe 2 MnSi has a low Curie temperature (220 K [16]), fails to follow the Slater-Pauling rule [16] and, in addition, has an antiferromagnetic arrangement of Mn ions [7,9]. Due to these reasons (Reviewer 1), this material is a good choice, since it is possible to verify if the nano-topology will improve those non-optimized physical properties.…”