97 research outputs found
Slater-Pauling Rule and Curie-Temperature of Co-based Heusler compounds
A concept is presented serving to guide in the search for new 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.
Further, it was found empirically that the Curie temperature of Co 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 CoFeSi is, actually, the half-metallic ferromagnet exhibiting
the highest magnetic moment and the highest Curie temperature measured for a
Heusler compound
Investigation of CoFeSi: The Heusler compound with Highest Curie Temperature and Magnetic Moment
This work reports on structural and magnetic investigations of the Heusler
compound CoFeSi. X-Ray diffraction and M\"o\ss bauer spectrometry indicate
an ordered structure. Magnetic measurements by means of X-ray magnetic
circular dichroism and magnetometry revealed that this compound is, currently,
the material with the highest magnetic moment () and Curie-temperature
(1100K) in the classes of Heusler compounds as well as half-metallic
ferromagnets
Half-Metallic Ferromagnetism in the Heusler Compound CoFeSi revealed by Resistivity, Magnetoresistance, and Anomalous Hall Effect measurements
We present electrical transport data for single-crystalline CoFeSi which
provide clear-cut evidence that this Heusler compound is truly a half-metallic
ferromagnet, i.e. it possesses perfect spin-polarization. More specifically,
the temperature dependence of is governed by electron scattering off
magnons which are thermally excited over a sizeable gap
() separating the electronic majority states at the Fermi level
from the unoccupied minority states. As a consequence, electron-magnon
scattering is only relevant at but freezes out at lower
temperatures, i.e., the spin-polarization of the electrons at the Fermi level
remains practically perfect for . The gapped magnon population
has a decisive influence on the magnetoresistance and the anomalous Hall effect
(AHE): i) The magnetoresistance changes its sign at , ii) the
anomalous Hall coefficient is strongly temperature dependent at and compatible with Berry phase related and/or side-jump electronic
deflection, whereas it is practically temperature-independent at lower
temperatures
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