We use neutron scattering to study the spin and charge/orbital ordering (CO-OO) in the nearly half-doped perovskite manganite $Pr_{ 0.55}(Ca_{ 0.8}Sr_{ 0.2})_{ 0.45}MnO_3$ (PCSMO). On cooling from room temperature, PCSMO first enters into a CO-OO state below $T_{ CO}$ and then becomes a CE-type long-range ordered antiferromagnet below $T_N$. At temperatures above $T_N$ but below $T_{ CO}$ ($T_N<T<T_{ CO}$), the spins in PCSMO form highly anisotropic smectic liquid-crystal-like texture with ferromagnetic (FM) quasi-long-range ordered one-dimensional zigzag chains weakly coupled antiferromagnetically. Such a magnetic smectic-like phase results directly from the spin-orbit interaction and demonstrates the presence of textured `electronic soft' phases in doped Mott insulators.
Categories: cond-mat.str-el