Half-metallic ferromagnetism with high magnetic moment and high Curie temperature in Co${}_2$FeSi

Co${}_2$FeSi crystallizes in the ordered L2${}_1$ structure as proved by X-ray diffraction and M"o\ss bauer spectroscopy. The magnetic moment of Co${}_2$FeSi was measured to be about $6{\mu }_B$ at 5K. Magnetic circular dichroism spectra excited by soft X-rays (XMCD) were taken to determine the element specific magnetic moments of Co and Fe. The Curie temperature was measured with different methods to be ($1100\pm 20$)K. Co${}_2$FeSi was found to be the Heusler compound as well as the half-metallic ferromagnet with the highest magnetic moment and Curie temperature.