Negative magnetization phenomenon in TbNiC

山本 将隆*; 日高 宏之*; 柳澤 達也*; 田端 千紘; 中尾 裕則*; 下村 晋*; 小野寺 秀也*; 網塚 浩*

Yamamoto, Masataka*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Tabata, Chihiro; Nakao, Hironori*; Shimomura, Susumu*; Onodera, Hideya*; Amitsuka, Hiroshi*

We report on the negative magnetization (NM) phenomenon characterized by a spontaneous magnetization antiparallel to an applied magnetic field in an antiferromagnetic (AFM) carbide TbNiC. The NM phenomenon in this compound is observed in the AFM state with a field cooling process at low magnetic fields below 500 Oe. The monotonic decrease in magnetization below the Neel temperature of 25 K observed in temperature dependence measurement of magnetization for TbNiC cannot be explained by Neel's classical theory of ferrimagnetism. We propose a novel ferrimagnetic model in which the NM originates from phase coupling between charge density wave and AFM orders.