Resonant Soft X-ray Scattering Study on Bilayer LaSr₂Mn₂O₇

Strongly correlated electron systems, for example colossal magnetoresistive materials, exhibit a strong competition among orbital, charge and spin order.  The emergence of interesting phenomena has been raised in maganites.  The phase diagram of the bilayer manganites, La_2-2xSr_1+2xMn₂O₇, display exotic ordering-features near half doping, x*0.5: LaSr₂Mn₂O7₊., and it has been commmonly accepted that charge-exchange (CE) order at x=0.5 is reentrant.  Further, due to the features, there is controversy on true ground state.  Here, we present exotic ordering states on half doping LaSr₂MN₂O₇ as well as near half doping LaSr₂Mn₂0₇+., using resonant soft x-ray scattering measurement.  From the scattering data, we offer a clue to the understanding of the true ground state on LaSr₂Mn₂O₇, as well as a solution of the controversy in this system