Versatile and competing spin-charge-orbital orders in the bilayered manganite system Pr(Sr1-yCay)2Mn2O7

Electronic-phase competition has been investigated for single crystals of half-doped bilayer-structure manganites, Pr(Sr1-yCay)(2)Mn2O7 (0 <= y <= 1.0), with controlled one-electron bandwidth (W). For y <= 0.4, the A-type antiferromagnetic (AF) state with x(2)-y(2) orbital order shows up as the ground state while accompanying the short-range vertical charge order with the periodicity of approximate to 4a(0) (a(0)approximate to 0.4 nm). For y>0.4, with reduced W, the CE-type AF state emerges with the ordered staggered orbitals (3x(2)-r(2)/3y(2)-r(2)) whose diagonal stripes undergo the 90 degrees rotation with decreasing temperature, perhaps coupled with the evolution of spin correlation.