부산대학교 도서관

Elastic and inelastic neutron scattering (ENS and INS) experiments were performed on a single crystal of (Ni0.4Mn0.6)TiO3 (NMTO) to study the spatial correlations and dynamics of spins in the XY-like spin-glass (SG) state. Magnetization measurements reveal signatures of SG behavior in NMTO with a freezing temperature of TSG ~ 9.1 K. The ENS experiments indicated that the intensity of magnetic diffuse scattering starts to increase around 12 K, which is close to TSG. Also, spin-spin correlation lengths (zeta) at 1.5 K are approximately (21) and (73) angstrom in the interlayer and the in-plane directions, respectively, demonstrating that magnetic correlations in NMTO exhibit quasi two-dimensional antiferromagnetic order. In addition, critical exponent (beta) is determined to be 0.37 from the intensity of magnetic diffuse scattering confirms the XY-like SG state of NMTO. INS results show quasi-elastic neutron scattering (QENS) profiles below TSG. The life-time of dynamic correlations obtained from the half width at half maximum of the Lorentzian QENS profiles, are approximately 16 and 16 ps at 10 K for two positions (0.00, 0.00, 1.52) and (0.01, 0.01, 1.50), respectively. Therefore, our experimental findings demonstrate that short-range-ordered antiferromagnetic clusters with short-lived spin correlations are present in the XY-like SG state of NMTO.
Comment: 20 pages, 7 figures