Search

A good field to develop new materials with half metallicity is the quaternary Heusler alloys. The preferred route is to combine the compounds that have been already grown in Heusler structure. As a typical example, the quaternary LiMgPdSb-type CoFeMnSi have been investigated in detail. For the quaternary LiMgPdSb-type compounds, three nonequivalent structures exist. From the calculated density of state (DOS) results, it can be seen that one superstructure shows half metallicity. The second superstructure has a pseudogap at the Fermi level. The third superstructure shows metallic behavior. Based on the analysis of the measured XRD pattern and magnetization curve, we can deduce that the CoFeMnSi compound is crystallized in the structure where half metallicity occurs. [ABSTRACT FROM AUTHOR]

Co2FeSi crystallizes in the ordered L21 structure as proven by x-ray diffraction and Möβbauer spectroscopy. The magnetic moment of Co2FeSi was measured to be about 6μB at 5 K. Magnetic circular dichroism spectra excited by soft x-rays were taken to determine the element-specific magnetic moments of Co and Fe. The Curie temperature was measured with different methods to be (1100±20)K. Co2FeSi was found to be the Heusler compound as well as the half-metallic ferromagnet with the highest magnetic moment and Curie temperature. [ABSTRACT FROM AUTHOR]

A concept is presented serving to guide in the search for materials with high spin polarization. It is shown that the magnetic moment of half-metallic ferromagnets can be calculated from the generalized Slater-Pauling rule. Furthermore, it was found empirically that the Curie temperature of Co2-based Heusler compounds can be estimated from a seemingly linear dependence on the magnetic moment. As a successful application of these simple rules, it was found that Co2FeSi is, actually, the half-metallic ferromagnet exhibiting the highest magnetic moment and the highest Curie temperature measured for a Heusler compound. [ABSTRACT FROM AUTHOR]

Heusler compounds are a remarkable class of materials with more than 1000 members and a wide range of extraordinary multi-functionalities including halfmetallic high-temperature ferri- and ferromagnets, multi-ferroics, shape memory alloys, and tunable topological insulators with a high potential for spintronics, energy technologies, and magneto-caloric applications. The tunability of this class of materials is exceptional and nearly every functionality can be designed. Co2-Heusler compounds show high spin polarization in tunnel junction devices and spin-resolved photoemission. Manganese-rich Heusler compounds attract much interest in the context of spin transfer torque, spin Hall effect, and rare earth free hard magnets. Most Mn2-Heusler compounds crystallize in the inverse structure and are characterized by antiparallel coupling of magnetic moments on Mn atoms; the ferrimagnetic order and the lack of inversion symmetry lead to the emergence of new properties that are absent in ferromagnetic centrosymmetric Heusler structures, such as non-collinear magnetism, topological Hall effect, and skyrmions. Tetragonal Heusler compounds with large magneto crystalline anisotropy can be easily designed by positioning the Fermi energy at the van Hove singularity in one of the spin channels. Here, we give a comprehensive overview and a prospective on the magnetic properties of Heusler materials [ABSTRACT FROM AUTHOR]

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=52.5 kJ m-3 and an average saturation magnetization of about 0.25μB/at. at 5 K. The saturation magnetization indicates a ferrimagnetic order with partially compensating moments at the Mn atoms on crystallographically different sites. The Curie temperature is above 730 K 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. [ABSTRACT FROM AUTHOR]

The article investigates the prediction of half-metallic ferromagnetism in Rb4O6 through magnetic measurements. The magnetic properties of Rb4O6 were measured using a superconducting quantum interference device. Samples of approximately 100 milligrams, fused in Suprasil tubes under a helium atmosphere were used for the analysis.

The quaternary intermetallic Heusler compounds CoFeMnZ (Z = Al, Ga, Si, or Ge) with 1 : 1 : 1 : 1 stoichiometry were predicted to exhibit half-metallic ferromagnetism by ab initio electronic structure calculations. The compounds were synthesized using an arc-melting technique and the crystal structures were analyzed using x-ray powder diffraction. The electronic properties were investigated using hard x-ray photoelectron spectroscopy. The low-temperature magnetic moments, as determined from magnetization measurements, follow the Slater-Pauling rule, confirming the proposed high spin polarizations. All compounds have high Curie temperatures, allowing for applications at room temperature and above. [ABSTRACT FROM AUTHOR]

Abstract: Electronic structure calculation were used to predict a new material for spintronic applications. is one example which is stable against on-site correlation and disorder effects due to the position of the Fermi energy in the middle of the minority band gap. Experimentally the sample were made exhibiting structure and a high magnetic order. [Copyright &y& Elsevier]

We present the synthesis of Co2FeGa Heusler nanowires and the results of our investigations on their three-dimensional (3D) electric and magnetic internal and external fields mapped by electron holographic tomography (EHT). These fields will be of great importance in next-generation nanomagnets integrated in spintronics and memory devices. The Co2FeGa nanowires with a L21 ordered structure are prepared by a SBA-15 silica-assisted method. The magnetic dipole-like stray fields of several Co2FeGa nanowires are revealed by holographically reconstructed phase images. Based on the measured magnetic phase shifts of an individual nanowire and its 3D reconstruction using EHT, we obtain an internal magnetic induction with a magnitude of 1.15 T and a nonmagnetic surface layer of 10 nm thickness. Furthermore, we also reconstruct the 3D distribution of the electrostatic potential of the same nanowire. [ABSTRACT FROM AUTHOR]