Novel Magnetic and Thermodynamic Properties of Thiospinel Compound CuCrZrS4_{4}

We have carried out dc magnetic susceptibility, magnetization and specific heat measurements on thiospinel CuCrZrS$_{4}$. Below $T_{\rm C}^{*} =$ 58 K, dc magnetic susceptibility and magnetization data show ferromagnetic behavior with a small spontaneous magnetization 0.27 $\mu_{\rm B}/$f. u.. In dc magnetic susceptibility, large and weak irreversibilities are observed below $T_{\rm f} =$ 6 K and in the range $T_{\rm f}< T < T_{\rm C}^{*}$ respectively. We found that there is no anomaly as a peak or step in the specific heat at $T_{\rm C}^{*}$.Comment: 11 pages, 4 figure

Electronic Structures of Fe3−xV_{3-x}V_x$Si Probed by Photoemission Spectroscopy

The electronic structures of the Heusler type compounds Fe$_{3-x}V$_x$Si in the concentration range between x = 0 and x = 1 have been probed by photoemission spectroscopy (PES). The observed shift of Si 2p core- level and the main valence band structres indicate a chemical potential shift to higher energy with increasing x. It is also clarified that the density of state at Fermi edge is owing to the collaboration of V 3d and Fe 3d derived states. Besides the decrease of the spectral intensity near Fermi edge with increasing x suggests the formation of pseudo gap at large x.Comment: 4 pages, 5 figures, 5 reference

Magnetic properties of Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition

Polycrystalline Ni2.18Mn0.82Ga Heusler alloys with a coupled magnetostructural transition are studied by differential scanning calorimetry, magnetic and resistivity measurements. Coupling of the magnetic and structural subsystems results in unusual magnetic features of the alloy. These uncommon magnetic properties of Ni2.18Mn0.82Ga are attributed to the first-order structural transition from a tetragonal ferromagnetic to a cubic paramagnetic phase.Comment: 4 pages, 4 figures, revtex

Carrier-mediated ferromagnetic ordering in Mn ion-implanted p+GaAs:C

Highly p-type GaAs:C was ion-implanted with Mn at differing doses to produce Mn concentrations in the 1 - 5 at.% range. In comparison to LT-GaAs and n+GaAs:Si samples implanted under the same conditions, transport and magnetic properties show marked differences. Transport measurements show anomalies, consistent with observed magnetic properties and with epi- LT-(Ga,Mn)As, as well as the extraordinary Hall Effect up to the observed magnetic ordering temperature (T_C). Mn ion-implanted p+GaAs:C with as-grown carrier concentrations > 10^20 cm^-3 show remanent magnetization up to 280 K

Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys

Using the full-potential screened Korringa-Kohn-Rostoker method we study the full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these compounds show a half-metallic behavior, however in contrast to the half-Heusler alloys the energy gap in the minority band is extremely small. These full-Heusler compounds show a Slater-Pauling behavior and the total spin-magnetic moment per unit cell (M_t) scales with the total number of valence electrons (Z_t) following the rule: M_t=Z_t-24. We explain why the spin-down band contains exactly 12 electrons using arguments based on the group theory and show that this rule holds also for compounds with less than 24 valence electrons. Finally we discuss the deviations from this rule and the differences compared to the half-Heusler alloys.Comment: 10 pages, 8 figures, revised figure 3, new text adde