Magnetism induced by interlayer electrons in the quasi-two-dimensional electride YC; Inelastic neutron scattering study

擬2次元エレクトライドYCにおける層間電子由来磁性

玉造 博夢   ; 村上 洋一*; 倉本 義夫*; 佐賀山 基*; 松浦 直人*; 川北 至信  ; 松石 聡*; 鷲尾 康仁*; 井下 猛*; 浜田 典昭*; 細野 秀雄*

Tamatsukuri, Hiromu; Murakami, Yoichi*; Kuramoto, Yoshio*; Sagayama, Hajime*; Matsuura, Masato*; Kawakita, Yukinobu; Matsuishi, Satoru*; Washio, Yasuhito*; Inoshita, Takeshi*; Hamada, Noriaki*; Hosono, Hideo*

Magnetic excitations in layered electride YC have been found by inelastic neutron scattering. We have observed weak but clear magnetic scattering around the wave number , but no magnetic order down to the lowest temperature measured (7 K). The imaginary part of the dynamical susceptibility deduced is well described by the Lorentz function of energy for each momentum . The width of the Lorentzian is proportional to with at K. We have also found that with increasing the magnetic form factor decays faster than that of a electron in a single Y atom, which indicates a more extended magnetic moment in YC. These results provide experimental evidence that the itinerant magnetism in YC originates from the anionic electrons that reside in the interlayers. The Curie-Weiss-like behavior of the magnetic susceptibility reported in YC is ascribed to the mode coupling effects of spin fluctuations.