Spin correlations in a frustrated spinel antiferromagnet LiCrMnO

Matsuda, Masaaki; Honda, Zentaro*; Katori, Hiroko*; Takagi, Hidenori*; Ueda, Hiroaki*; Ueda, Yutaka*; Mitamura, Hiroyuki*; Kindo, Koichi*

LiCrMnO shows an interesting behavior in magnetic field. Magnetization in LiCrMnO gradually increases and saturates at 1/2 of the full moment (3). This phenomenon is similar to the half-magnetization plateau observed in ACrO (A: Cd and Hg), which originates from a strong spin-lattice coupling. We performed neutron scattering experiments in LiCrMnO4 in magnetic field up to 10 T to clarify the origin of the plateau-like state. It was found that the magnetic peak at 0.6 is suppressed with increasing magnetic field although the magnetic peak at 1.6 is robust. This result suggests that the saturation of the magnetization is not related with the spin-lattice coupling as in ACrO but spins in phase 2 first align ferromagnetically in low magnetic field. This indicates that the magnetic interactions in phase 2 are relatively small, suggesting that the phase 2 is formed by further-neighbor interactions.