| Abstrakt: |
We successfully synthesized polycrystalline samples of Y2M3Co9P7 (M = Cr, Mn, Fe, Co, Mo, and Ru), which has the Zr2Fe12P7-type hexagonal structure with M and Co selectively occupy the pyramidal site and three tetrahedral ones, respectively. For the case of M = Co, or Y2Co12P7, the itinerant electronic ferromagnetism was observed below the Curie temperature TC = 153 K. For M = Cr, Mn, Fe, and Ru, the ferromagnetism was also observed below TC = 167 K, 229 K, 233 K and 18 K, respectively, whereas for M = Mo, an exchange-enhanced Pauli paramagnetism tool the place of the ferromagnetism. Among compounds with M being 3d transition metals, TC and spontaneous magnetization took the maximum around M = Fe and Mn. This tendency was also seen in the cases of M being 4d transition metals, i.e., M = Ru and Mo. Our result indicates that magnetic moments at the pyramidal site have rather localized nature and largely affect the stability of the ferromagnetism of Y2M3Co9P7 although the ferromagnetism is considered to be mainly derived from three Co sites. |
