Observation of gyromagnetic reversal
Imai, Masaki ; Ogata, Yudai*; Chudo, Hiroyuki ; Ono, Masao ; Harii, Kazuya; Matsuo, Mamoru*; Onuma, Yuichi*; Maekawa, Sadamichi; Saito, Eiji
We report direct observation of gyromagnetic reversal, which is the sign change of gyromagnetic ratio in a ferrimagnet HoFeO, by using the Barnett effect measurement technique at low temperatures. The Barnett effect is a phenomenon in which magnetization is induced by mechanical rotation through the coupling between rotation and total angular momentum of electrons. The magnetization of HoFeO induced by mechanical rotation disappears at 135 K and 240 K. The temperatures correspond to the magnetization compensation temperature and the angular momentum compensation temperature , respectively. Between and , the magnetization flips over to be parallel against the angular momentum due to the sign change of gyromagnetic ratio. This study provides an unprecedented technique to explore the gyromagnetic properties.