Study on Site Preference and Electronic State of Y<sub>2</sub>(Mn<sub><i>x</i></sub>Fe<sub>1−<i>x</i></sub>)<sub>12</sub>P<sub>7</sub> with the Zr<sub>2</sub>Fe<sub>12</sub>P<sub>7</sub>-type Structure

We studied a solid-solution system of the transition-metal pnictide, Y2(MnxFe1−x)12P7, with Zr2Fe12P7-type structure, which has two kinds transition metal sites: three tetrahedral sites and pyramidal site. successfully obtained polycrystalline samples Y2(MnxFe1−x)12P7 in range 0 ≦ x 0.9. The lattice parameter along a-axis monotonically increases Mn substitution, while that c-axis is nearly constant. 57Fe Mössbauer spectroscopy shows atoms prefer to occupy At = 0.25, site-ordered compound, Y2Mn3Fe9P7, was obtained, where site Fe sites. magnetization Y2Mn3Fe9P7 exhibits an anomaly at approximately 60 K, suggesting presence antiferromagnetic transition, originates from magnetic moment