SEPARATION OF SPIN AND CHARGE-DENSITIES IN LA2NIO4+DELTA

Separation of spin and charge densities in La2NiO4+delta was investiga ted using Raman scattering. Magnetic and electronic Raman scattering i n La2NiO4+delta with delta = 0.02 and delta = 0.15 has a large continu um below 1500 cm(-1). As temperature decreases to below 250 K at delta = 0.15: the scattering intensity below 650 cm(-1) moves into the high -energy range and simultaneously the intensity at the energy of the un doped two-magnon peak increases, as expected from the separation of sp in and charge densities. Similar effects are also observed even at the low carrier concentration of delta = 0.02 below 150 K. This indicates that the spin and charge densities separate even at the low carrier c oncentration of delta = 0.02.