NpIn study by neutron scattering under magnetic field

Mizuno, Fumio; Sugai, Takashi; Kaneko, Koji   ; Metoki, Naoto   ; Haga, Yoshinori   ; Aoki, Dai*; Homma, Yoshiya*; Shiokawa, Yoshinobu*

NpIn has the AuCu-type cubic structure. The structure is the same as the pressure-induced superconductor CeIn. It was reported that NpIn orders ferromagnetcally below T = 14 K and antiferromagnetically at T = 10 K, and a new field-induced phase (AF+FM) is found by the magnetization measurement. We reported the (0.5 0.5 0) and (0.5 0.5 1) magnetic reflections the last time. But we was not be able to determine the magnetic structure. This time, we study Q = (0.5 0.5 0) by the horizontal magnet. In the case of QH, the magnetic peak is observed, while in the case of QH, the magnetic peak is not observed. Using the relation of Q sin, where is the angle between Q and a magnetic moment, we find that antiferromagnetic modulation component and the external field are parallel. That is, we come to a conclusion that the structure in which the magnetic moments expand and contract along the external field is stable.