Electronically smecticlike liquid-crystal phase in a nearly half-doped manganite

Abstract

We use neutron scattering to study the spin and charge-orbital ordering (CO-OO) in the nearly half-doped perovskite manganite ${\mathrm{Pr}}_{0.55}{({\mathrm{Ca}}_{0.8}{\mathrm{Sr}}_{0.2})}_{0.45}\mathrm{Mn}{\mathrm{O}}_{3}$ (PCSMO). On cooling from room temperature, PCSMO first enters into a CO-OO state below ${T}_{\mathit{CO}}$ and then becomes a CE-type long-range ordered antiferromagnet below ${T}_{N}$. At temperatures above ${T}_{N}$ but below ${T}_{\mathit{CO}}$ $({T}_{N}<T<{T}_{\mathit{CO}})$, 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 smecticlike phase results directly from the spin-orbit interaction and demonstrates the presence of textured ``electronic soft'' phases in doped Mott insulators.