Abstract
We use neutron scattering to investigate the doping evolution of the
magnetic correlations in the single-layer manganite $\rm
Pr_{\it 1-x}Ca_{\it 1+x}MnO_4$, away from the $x=0.5$ composition where the
CE-type commensurate antiferromagnetic (AF) structure is stable. We
find that short-range incommensurate spin correlations develop as
the system is electron doped ($x<0.5$), which coexist with the
CE-type AF order. This suggests that electron doping in this system
induces an inhomogeneous electronic self-organization, where
commensurate AF patches with $x=0.5$ are separated by electron-rich
domain walls with short range magnetic correlations. This behavior
is strikingly different than for the three-dimensional $\rm Pr_{\it
1-x}Ca_{\it x}MnO_3$, where the long-range CE-type commensurate AF
structure is stable over a wide range of electron or hole doping
around $x=0.5$.
