This work reports about the electronic, magnetic, and structural properties of the binary compound Mn3Ga. The tetragonal DO22 phase of Mn3Ga was successfully synthesized and investigated. It has been found that the material is hard magnetic with an energy product of Hc×Br=52.5kJm−3 and an average saturation magnetization of about 0.25μB∕at. at 5K. The saturation magnetization indicates a ferrimagnetic order with partially compensating moments at the Mn atoms on crystallographically different sites. The Curie temperature is above 730K where the onset of decomposition is observed. The electronic structure calculations indicate a nearly half-metallic ferrimagnetic order with 88% spin polarization at the Fermi energy.

This paper reports on the bulk properties of the quaternary Heusler alloy ${\mathrm{Co}}_2{\mathrm{Mn}}_{1-x}{\mathrm{Fe}}_x\mathrm{Si}$ with the Fe concentration $x=0,1∕2,1$. All samples, which were prepared by arc melting, exhibit $L{2}_1$ long-range order over the complete range of Fe concentration. The structural and magnetic properties of the ${\mathrm{Co}}_2{\mathrm{Mn}}_{1-x}{\mathrm{Fe}}_x\mathrm{Si}$ Heusler alloys were investigated by means of x-ray diffraction, high- and low-temperature magnetometry, Mössbauer spectroscopy, and differential scanning calorimetry. The electronic structure was explored by means of high-energy photoemission spectroscopy at about $8\mathrm{keV}$ photon energy. This ensures true bulk sensitivity of the measurements. The magnetization of the Fe-doped Heusler alloys is in agreement with the values of the magnetic moments expected for a Slater-Pauling-like behavior of half-metallic ferromagnets. The experimental findings are discussed on the basis of self-consistent calculations of the electronic and magnetic structure. To achieve good agreement with experiment, the calculations indicate that on-site electron-electron correlation must be taken into account, even at low Fe concentration. The present investigation focuses on searching for the quaternary compound where the half-metallic behavior is stable against outside influences. Overall, the results suggest that the best candidate may be found at an iron concentration of about 50%.

Band Jahn–Teller type structural instabilities of cubic Mn₂YZ Heusler compounds causing tetragonal distortions can be predicted by ab initio band‐structure calculations. This allows for identification of new Heusler materials with tunable magnetic and structural properties that can satisfy the demands for spintronic applications, such as in spin‐transfer torque‐based devices.

This work reports on the electronic, magnetic, and structural properties of the binary intermetallic compounds ${\mathrm{Mn}}_{3-x}\mathrm{Ga}$. The tetragonal ${\mathrm{DO}}_{22}$ phase of the ${\mathrm{Mn}}_{3-x}\mathrm{Ga}$ series, with $x$ varying from 0 to 1.0 in steps of $x=0.1$, was successfully synthesized and investigated. It was found that all these materials are hard magnetic, with energy products ranging from $10.1\mathrm{kJ}{\mathrm{m}}^{-3}$ for low Mn content $(x\to 1)$ to $61.6\mathrm{kJ}{\mathrm{m}}^{-3}$ for high Mn content $(x\to 0)$. With decreasing Mn content, the average saturation magnetization per atom increases from $0.26{\mu }_B$ for ${\mathrm{Mn}}_3\mathrm{Ga}$ to $0.47{\mu }_B$ for ${\mathrm{Mn}}_2\mathrm{Ga}$. The increase in the saturation magnetization as the Mn content is reduced indicates a ferrimagnetic order with partially compensating moments of the two different Mn atoms on the two crystallographically different sites of the ${\mathrm{DO}}_{22}$ structure. This type of magnetic order is supported by ab initio calculations of the electronic structure that predict a nearly half-metallic ferrimagnet with the highest spin polarization of 88% at the Fermi energy for ${\mathrm{Mn}}_3\mathrm{Ga}$. The Curie temperature of the compounds is restricted to approximately $770\mathrm{K}$ because of a structural phase transition to the hexagonal ${\mathrm{DO}}_{19}$ phase. Thermal irreversibilities between zero-field-cooled and field-cooled measurements suggest that the ${\mathrm{Mn}}_{3-x}\mathrm{Ga}$ series belongs to the class of magnetically frustrated ferrimagnets. The most pronounced magnetic anomaly is found for ${\mathrm{Mn}}_3\mathrm{Ga}$.