Magnetic Susceptibility of Doped Si Nanowhiskers

Abstract

The present paper deals with studies of magnetic properties of Si(B) whiskers with large boron impurity concentration of up to 1-5% in the range of magnetic fields (0.3-4.0) kOe and temperatures of 4.2-300 K. In particular, magnetic susceptibility of whiskers has been investigated. The results obtained in the temperature range of 77-300 K have shown that magnetic susceptibility of whiskers substantially differs from that of bulk Si, which is revealed in the two significant peculiarities: (1) a substantial paramagnetic contribution into whisker magnetization and magnetic susceptibility; (2) a non-linear dependency of magnetization on magnetic field intensity. These facts indicate an existence of magnetic ordering in whiskers. The observed magnetization hysteresis at 4.2 K confirms the above supposition. Possible reasons of the observed effects have been discussed.

Magnetic Properties of Doped Si<B,Ni> Whiskers for Spintronics

“…It is well known [18,19], that the presence of magnetic impurities in diluted magnetic semiconductors leads to both the hysteresis of magnetic moment and in some cases to the hysteresis of magnetoresistance in the crystals. Thus, during the experimental research of the silicon whiskers the hysteresis of magnetization was observed, that suggests a certain magnetic ordering [20]. One can suggest that magnetic centers are created due to interactions of magnetic orbital moments of dangling bonds with delocalized impurity states of the upper Hubbard band in heavily doped Si with boron concentration in the vicinity of the metal-insulator transition.…”

Magnetic susceptibility and magnetoresistance of neutron-irradiated doped SI whiskers

“…More detail investigation of magnetoresistance has shown the existing of hysteresis loop, which is observed at around liquid helium temperatures and disappears at 6-7 K (at temperature of disappearance of magnetic susceptibility hysteresis [14]). …”

Superparamagnetism in Si1 – xGex (B, Hf) Whiskers

“…The specific magnetic properties of Sibased whiskers are related to their core-shell structure [4], in particular, to the presence in the porous shell of Si nanowires of a high concentration of dangling bonds, which are known to be paramagnetic centers [5]. The interaction of paramagnetic centers in pores of small size can lead to low magnetization hysteresis in crystals at low temperatures [6].…”