Positive magnetoresistance and orbital ordering in La(1-x)Sr(x)MnO(3)
  We report on detailed transprort measurements of single crystalline La(1-x)Sr(x)MnO(3) (x<=0.2). We have found a giantpositive magnetoresistance in the compositions range between 0.1<=x<=0.125 and give an explaination in terms of orbital ordering due to the interplay between superexchange interactions and Jahn-Teller distortions. 
M. Paraskevopoulos, J. Hemberger, A. Loidl, A. A. Mukhin, V. Yu.   Ivanov and A. M. Balbashov