  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.

Strongly Correlated Electrons