Reentrant Orbital Order and the True Ground State of LaSr2Mn2O7

Authors :: Li, Qing'An
Gray, K. E.
Zheng, H.
Claus, H.
Rosenkranz, S.
Ancona, S. Nyborg
Osborn, R.
Mitchell, J. F.
Chen, Y.
Lynn, J. W.
Source :: Phys. Rev. Lett. 98, 167201 (2007)
Publication Year :: 2007
Abstract: Contrary to conventional wisdom, our purified La2-2xSr1+2xMn2O7 crystals exhibit CE-type orbital and charge order as the low-temperature ground state for a hole doping level h = 0.5. For small deviations from h = 0.5, the high temperature CE phase is replaced at low temperatures by an A-type antiferromagnet without coexistence. Larger deviations result in a lack of CE order at any temperature. Thus, small inhomogeneities in cation or oxygen composition could explain why others commonly see this reentrance with coexistence.<br />Comment: 4 pages, RevTex4