Enhancement of the anomalous Hall effect and spin glass behavior in the   bilayered manganite La(2-2x)Sr(1+2x)Mn2O7
  The Hall resistivity and magnetization have been investigated in the ferromagnetic state of the bilayered manganite La(2-2x)Sr(1+2x)Mn2O7 (x=0.36). The Hall resistivity shows an increase in both the ordinary and anomalous Hall coefficients at low temperatures below 50K, a region in which experimental evidence for the spin glass state has been found in a low magnetic field of 1mT. The origin of the anomalous behavior of the Hall resistivity relevant to magnetic states may lie in the intrinsic microscopic inhomogeneity in a quasi-two-dimensional electron system. 
Y. Hirobe, Y. Ashikawa, R. Kawasaki, K. Noda, D. Akahoshi, and H.   Kuwahara