Charge and spin dynamics of an ordered stripe phase in La12/3Sr1/3NiO4 investigated by Raman spectroscopy

Fur La12/3Sr1/3NiO4, a commensurately doped Mott-Hubbard system, charge and spin ordering in a stripe has been investigated by phonon and magnetic Raman scattering. Formation of a superlattice and an opening of a pseudogap in the electron-hole excitation spectra as well as two types of double-spin excitations - within the antiferromagnetic domain and across the domain wall-are observed below the charge ordering transition. The temperature dependence suggests that the spin ordering is driven by charge ordering and that fluctuating stripes persist above the ordering transition.