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 Ho
Fe
O
, 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 Ho
Fe
O
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.