Inelastic neutron scattering study on anisotropic spin glass Fe2TiO5*

Of all the spin glasses systems, Fe2TiO5 is a unique member due to its anisotropic spin glass transition along the c-axis, despite having purely isotropic spins. This has been interpreted as a longitudinal freezing prior to transverse ones in the presence of weak random anisotropy. However, our recent diffuse neutron scattering experiment [1]demonstrated that nanoscale surfboard shaped antiferromagnetic regions arise below the glass transition temperature and possess strong transverse spin fluctuations which can lead to uniaxial spin glass freezing in Fe2TiO5, implying the significant role of spin fluctuations in this system. To further understand this, we have performed an  inelastic neutron scattering study of the spin fluctuations in Fe2TiO5 single crystals and investigated the temperature- and energy- dependence of the low energy excitation spectra. These results unveil the complicated magnetic interactions in Fe2TiO5 and shed light on understanding its unique behavior from a new perspective.