High in-plane magnetic field gradients, as large as 6 x 10(4) T/m, pro
duced with a magnetized thin dysprosium stripe, are used to control th
e lateral motion of excitons in a 8 nm In0.2Ga0.8As quantum well. By m
easuring the exciton photoluminescence (PL) energy and intensity, spat
ially resolved with mu m resolution. it is shown that diamagnetic exci
tons are forced to regions of low magnetic field, due to the interacti
on of the magnetic moment with the non-homogeneous field.