Remarkable room‐temperature magnetoresistance in silicon strip devices

 

(2016)  

3 

 

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Rapid

Research Letter

 

Figure 3

 MR ratios in (a) one-top-contact and (b) ten-top-contact 

measuring configurations as a function of the magnetic field for 

different applied voltages. 

 

Different from the results in the one-top-contact meas-

urement, the MR ratio in the ten-top-contact measurement 

has no saturation in the corresponding parameter range. 

For all applied voltages, the MR ratio first increases and 

reaches a maximum at 0.8 T, and then decreases to a mi-

numum around 1.0 T. After that, the MR ratio rises again 

with the magnetic field. It is worth noting that the largest 

MR ratio of 

∼

155% at the applied voltage of 1.0 V and 

magnetic field of 1.2 T is much smaller than the value of 

∼

400% in the one-top-contact measurement at the same bi-

as voltage but a weaker magnetic field of 0.8 T.  

To understand the difference between the MRs in one-

top-contact and ten-top-contact measurements, the MR ra-

tio with the magnetic field is investigated for the measur-

ing configurations with different top contact numbers. It is 

found that with increasing the contact number, the MR ra-

tio change trend with the magnetic field gradually evolves 

from the one-top-contact case (Fig. 3(a)) to the ten-top-

contact case (Fig. 3(b)) and the MR ratio value gradually 

reduces, as demonstrated by the representative measure-

ments with four- and seven-top-contacts shown in Fig. 4(a) 

and (b), respectively. For the four-top-contact measure-

ment, the MR ratio first exhibits saturation in the magnetic 

field range of 0.4 T to 0.7 T (similar to one-top-contact 

measurement) and then slightly increases after 0.7 T. The 

MR ratio in the seven-top-contact measurement increases 

with the magnetic field and reaches a maximum at 0.8 T, 

and then decreases (similar to top-ten-contact measurement). 

One notes that the current should increase with the top con-

tact number, which would enhance the Hall electric field. 

Accordingly, for the one-top-contact case, the Hall electric 

field is relatively weak and the Lorentz force dominates the 

carrier movement, resulting in strong carrier scattering and 

thus the large MR ratio. Moreover, as the magnetic field in-

creases, carrier scattering mainly caused by the Lorentz 

force is gradually saturated, leading to the saturated MR ra-

tio for the one-top-contact measurement. With the increase 

of the top contact number, the increased current enhances 

the Hall electric field, which would partly counteract the in-

fluence on carrier scattering by the Lorentz force. Accord-

ingly, the MR ratio gradually reduces and meanwhile be-

come relatively difficult in saturation with the magnetic field 

as the top contact number increases. Anyway, it is worth 

noting that the above information just roughly and qualita-

tively explains the MR difference. For a more quantitative 

physical picture, more investigations are necessary.