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Electrical-physical and galvanomagnetic properties

Using the swift heavy ion tracks, a structure n-Si/SiO2/Ni (fig.1). A schematic diagram of contacts placement on the Si/SiO2/Metal structure for measurements of electrical-physical and galvanomagnetic properties:

Fig.1. Schematic representation of Si/SiO2/Metal structure: 1 – Metal in pores; 2 – Silicon oxide layer; 3 – Silicon substrate; 4 – Current contacts; 5 – Potential contacts; 6 – Hall contacts



Fig.2. Current-voltage characteristics of samples with metal clusters in SHI tracks at the liquid nitrogen and room temperatures


Based on a series of experiments (fig.3) determined that the system Si/SiO2/Ni in different temperature ranges dominated by a few mechanisms of electromigration (fig.5).

Fig.3. Temperature dependences of resistance in zero magnetic field and in the field 12 T.


Investigations of electrical-physical and galvanomagnetic properties  of S/SiO2/Ме (Cu, Ni) samples in temperature range  4-300 K and magnetic fields up to  14 T were carried out on the universal measurement system "TAE EV 031" ("Cryogenic Limited" company) (fig.4).

Fig.4. The universal measurement system "TAE EV 031" ("Cryogenic Limited" company)


Mechanisms of electron transport in different temperature ranges:

  • At T = 300 - 210 K the conductivity is made by electrons located in the upper energy levels of the conduction band of Si, and we have them over-barrier emission in metal
  • At temperatures of 210 - 35 K due to freezing of the electronic states at the upper levels of the process of electromigration excluded clusters of nickel in the pores
  • At temperatures below 35 K, when in fact it becomes an insulator silicon electron transport in part through the clusters in the pores, and pores between at the interface of Si/SiO2.

Fig. 5. Schematic representation of the mechanisms of charge transport in the structure n-Si/SiO2/Ni in different temperature regions.



At low temperatures (18 - 50 K) in structures containing nickel clusters revealed the presence of a positive magnetoresistance, which grows with decreasing temperature, reaching at T = 20 K value of 1000% (Fig. 6).

Fig 6. A plot of the magnetoresistance of the structure n-Si/SiO2/Ni at low temperatures.


On the basis of this dependence is possible to create highly sensitive sensors of magnetic devices for space application, operating at liquid-hydrogen cooled.



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