High-energy magnetic excitations in lightly oxygen-doped lanthanum nickel oxides

酸素ドープしたランタンニッケル酸化物の磁気励起の二重性

中島 健次  ; 梶本 亮一  

Nakajima, Kenji; Kajimoto, Ryoichi

We will report on magnetic excitations in lightly oxygen doped lanthanum nickel oxide, LaNiO. By introducing slightly excessive oxygen atoms in the system, magnetic excitations in LaNiO drastically changes its picture. In lower energy region, spin-wave stiffness strongly suppressed. On the other hand, in the higher energy region, spin-wave dispersion curve is almost same as in the stoichiometric system, while excitations show considerable broadening. Alternation of the character of the excitations by changing energy is also reported in hole doped cuprates and cobalates. We consider that this behavior is one of key clues to understand magnetism and transport properties in carrier doped layered transition metal oxides. We investigated detail of magnetic excitations in two different lightly doped systems, LaNiO and LaNiO in wide momentum and energy transfer space by using time-of-flight spectrometers at J-PARC. Observed doping effects in magnetic excitations will be discussed by comparing them to those reported in other related layered transition metal oxides.