Electronically smectic-like phase in a nearly half-doped manganite

Charge/orbital ordering is one of the most important of phenomena in doped manganites [1-3]. In this talk, I am going to present our recent neutron scattering results on the charge/orbital ordering (CO-OO) and spin ordering in the nearly half-doped perovskite manganite Pr$_{0.55}$(Ca$_{0.8}$Sr$_{0.2})_{0.45}$MnO$_{3}$ (PCSMO) [4]. 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 TN. At temperatures above TN but below T$_{CO}$ (T$_{N} \quad <$ 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 [5,6]. This work was supported by the DOE No.DE-AC05-00OR22725 with UT/Battelle, LLC and U. S. NSF DMR-0139882. This work was performed under the US-Japan Cooperative Program on Neutron Scattering. \newline \newline [1] J. van den Brink et al., Phys. Rev. Lett. 83, 5118 (1999). \newline [2] I. V. Solovyev and K. Terakura, Phys. Rev. Lett. 83, 2825 (1999). \newline [3] I. V. Solovyev, Phys. Rev. Lett. 91, 177201 (2003). \newline [4] F. Ye et al., Phys, Rev. B. (in press) \newline [5] G. C. Milward et al., Nature 433, 607 (2005). \newline [6] S. A. Kivelson et al., Nature 393, 550 (1998).