Phase separation, charge-density waves, and magnetism in La[sub 2]NiO[sub 4+[delta]] with [delta]=0. 105

Neutron diffraction measurements on a highly doped single crystal of La[sub 2]NiO[sub 4+[delta]] ([delta]=0.105) reveal that below room temperature the crystal undergoes phase separation into an orthorhombic structure, with a doubled unit cell along [ital c], and a tetragonal phase. The lattice distortion in the orthorhombic phase suggests charge-density-wave order, and related diffuse scattering is observed at room temperature. The orthorhombic phase orders antiferromagnetically below 55 K with a significant ordered moment ([similar to]0.7[mu][sub [ital B]]).