  The semiconducting half-Heulser compound DyNiBi shows a negative giant
magnetoresistance (GMR) below 200 K. Except for a weak deviation, this
magnetoresistance scales roughly with the square of the magnetization in the
paramagnetic state, and is related to the metal-insulator transition. At low
temperature, a positive magnetoresistance is found, which can be suppressed by
high fields. The magnitude of the positive magnetoresistance changes slightly
with the amount of impurity phase.
