Quantum magnetoresistance in Si <B, Ni> whiskers

It was studied the electrical magnetoresistance of nickel-and boron-doped filamentary silicon crystals in which a metal-insulator transition is observed. A giant magnetoresistance reaches up to 280% in the Si whiskers with doping concentration of boron р300K = 5⋅1018 cm−3 in the magnetic fields with induction up to 14 T at temperature 4.2 K. Peculiarities of magnetoresistance at low temperatures were shown to be caused by “core-shell” structure of crystals. A giant magnetoresistance nature was considered within quantum magnetoresistance model. The analysis was performed to determine the critical field of transition from classical parabolic magnetoresistance to quantum magnetoresistance, realized in the near-surface region of the crystal. The silicon whiskers were used for design of magnetic field sensors.