A local metallic state in globally insulating   $La_{1.24}Sr_{1.76}Mn_2O_7$ well above the metal-insulator transition
  Angle-resolved photoemission spectroscopy was used to investigate the evolution of the electronic structure across the metal-insulator transition in bi-layer manganite $La_{1.24}Sr_{1.76}Mn_2O_7$. We found that this system is a metal for $T<T_C$, a local metal but global insulator for $T<T_C<T^*$, and a global insulator for $T>T^*$. These results indicate the critical role of electronic phase separation and percolation effects for the metal-insulator transition in $La_{1.24}Sr_{1.76}Mn_2O_7$. 
Z. Sun, J. F. Douglas, A. V. Fedorov, Y. -D. Chuang, H. Zheng, J. F.   Mitchell, D. S. Dessau