High spin polarization in the disordered quaternary Heusler alloy FeMnVGa

CoMnCrGa: a novel ferromagnetic material with high spin-polarization for room temperature spintronics

“…The contribution to magnetic Bragg peaks is not known to yield more than 2–3% of nuclear Bragg peaks. 20,31,33 Therefore, our analysis of ND spectra at 300 K considering only the lattice Bragg contributions would not be far off from that expected for a paramagnetic state.…”

“…51 Neutron diffraction has already proved their merits for such difficult cases. 20,31,33,52,53 Fig. 3 represents the powder neutron diffraction pattern taken at 300 K. For Heusler alloys, the presence of (111) and (200) Bragg peaks in the diffraction pattern is generally considered to be indicative of a well-ordered crystal structure.…”

“…Standard EXAFS measurement protocols have been used as detailed elsewhere. 20,31 High-temperature VSM (Model EV9, MicroSense, LLC Corp., USA) was used to measure the magnetization ( M ) vs. temperature ( T ) in the range of 300–900 K. M vs. field ( H ) measurement was carried out using a superconducting quantum interference vibrating sample magnometer (Quantum design Inc.,USA) in the magnetic fields up to ±70 kOe at 5 K. Four-probe resistivity measurement in the absence of a magnetic field was carried out in a Physical Property Measurement System (Quantum Design Inc., USA).…”

“…14–17 As a result of this substitution, the crystal structure transforms to a lower symmetry space-group, where the 8c site in the Fm 3̄ m space group splits into 4c and 4d sites in the F 4̄3 m space group. Recently, quaternary Heusler alloys attracted a lot of attention from the research community due to their HMF, 18–22 spin-gapless semiconductors, 23–28 spin-semimetal, 29 spin glass, 30 re-entrant spin glass 31 and bipolar magnetic semiconducting properties. 32 However, the structural disorder, which is quite inherent for Heusler alloys, is known to have a significant impact on the magnetic as well as the electronic structure.…”

“…Additionally, many of the predicted systems do not even form in a single phase, and to the best of our knowledge, only a few such compounds have been experimentally realized so far. Recently, FeMnVAl 19 and FeMnVGa 20 were found to show robust half-metallicity even in the presence of structural disorder. However, the Curie temperature for FeMnVAl is 213 K and for FeMnVGa is close to room temperature (293 K).…”