Magnetic susceptibility and magnetoresistance of neutron-irradiated doped SI whiskers

• Neutron irradiation influence on magnetic susceptibility of Si whiskers is studied.
• Neutron irradiated Si whiskers with boron concentration away of MIT are diamagnetic.
• Whiskers in the vicinity to MIT showed hysteresis loops in magnetoresistance.
• Whiskers in the vicinity to MIT showed hysteresis loops in magnetic susceptibility.

The effect of 8.6·1017 n/cm2 fast neutron irradiation on the magnetic susceptibility and magnetoresistance of Si whiskers with impurity concentration near metal–insulator transition (MIT) has been studied. Neutron irradiated specimens with boron concentration away of MIT are mainly diamagnetic with a small amount of paramagnetic centers originated from dangling bonds on the whisker surface. It has been established that at temperatures near 4.2 K, a significant contribution to the conductivity is made by light charge carriers of low concentration but with high mobility. The as grown whiskers with impurity concentration correspondent to MIT showed hysteresis loops in magnetization at temperature of liquid helium. Besides hysteresis loops in magnetoresistance was observed for whiskers under compression stress at low temperature up to 7 K. The possible reason of the effect can be magnetic interaction between impurities centers in subsurface region of the whisker with the orbital moment of dangle bounds in the whisker core–shell interstices.

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