The addition of impurities to a semiconductor for the purpose of modifying its electrical conductivity; in this study it is hoped that doping with various elements (i.e. Ni) will increase the magnetoresistance.
The introduction of an element that alters the conductivity of a semiconductor. Adding boron to silicon will create a P-type (more positive) material, while adding phosphorus or arsenic to silicon will create N-type (more negative) material.
The substitution of atoms in a semiconductor by species of a different valence to the host species, such that extra charge carriers, electrons or positive holes, are introduced and the conductivity of the semiconductor is increased.