2.15 Exercises
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40. What are the main issues limiting the design of spintronic devices?
41. What is spin filtering?
42. How was the spin-polarized electron transport across the ferromagnetic and
semiconductor interface verified?
43. What is the role of barrier layer on controlling the spin filtering?
44. What is spin Hall effect?
45. What is the origin of spin Hall effect?
46. What are the differences between the classical and spin Hall effect?
47. What are the factors determine the spin injection efficiency?
48. Why does the spin accumulate at the interface between the ferromagnetic and
non-magnetic?
49. How can we control the spin polarization of the injected current?
50. How do we achieve large spin accumulation in the semiconductor?
51. Multiple Choice Questions
(a) Density of states spin polarization is negative for Co and Ni. Which of
the following statement is correct?
(i) Minority spin contribution is dominant at Fermi level.
(ii) Majority spin contribution is dominant at Fermi level.
(iii) Majority and minority spin contribution is equal at Fermi level.
(b) Current density carried by the majority and minority spin electrons in
a ferromagnet is given by 70% and 30% of the total current density,
respectively. Spin injection efficiency is given by
(i) 0.6
(ii) 0.4
(iii) 0.7
(c) Let us consider an Ohmic contact between a ferromagnetic (Co) and
a paramagnetic (Cu) metal. The resistivity of Co and Cu is 10 and 1
μ cm, respectively. What will be the value of the ratio between spin
injection efficiency and conductivity polarization of the Co?
(i) 1.1
(ii) 0.1
(iii) 0.9
(d) In case of a tunnelling barrier between ferromagnetic metal and paramagnetic semiconductor, the spin injection efficiency is 0.70. What is the
value of the polarization of the tunnelling conductivity at the interface?
(i) 0.3
(ii) 0.5
(iii) 0.7
(e) In case of a Schottky barrier between a ferromagnetic metal and
paramagnetic semiconductor interface, we obtain
71
40. What are the main issues limiting the design of spintronic devices?
41. What is spin filtering?
42. How was the spin-polarized electron transport across the ferromagnetic and
semiconductor interface verified?
43. What is the role of barrier layer on controlling the spin filtering?
44. What is spin Hall effect?
45. What is the origin of spin Hall effect?
46. What are the differences between the classical and spin Hall effect?
47. What are the factors determine the spin injection efficiency?
48. Why does the spin accumulate at the interface between the ferromagnetic and
non-magnetic?
49. How can we control the spin polarization of the injected current?
50. How do we achieve large spin accumulation in the semiconductor?
51. Multiple Choice Questions
(a) Density of states spin polarization is negative for Co and Ni. Which of
the following statement is correct?
(i) Minority spin contribution is dominant at Fermi level.
(ii) Majority spin contribution is dominant at Fermi level.
(iii) Majority and minority spin contribution is equal at Fermi level.
(b) Current density carried by the majority and minority spin electrons in
a ferromagnet is given by 70% and 30% of the total current density,
respectively. Spin injection efficiency is given by
(i) 0.6
(ii) 0.4
(iii) 0.7
(c) Let us consider an Ohmic contact between a ferromagnetic (Co) and
a paramagnetic (Cu) metal. The resistivity of Co and Cu is 10 and 1
μ cm, respectively. What will be the value of the ratio between spin
injection efficiency and conductivity polarization of the Co?
(i) 1.1
(ii) 0.1
(iii) 0.9
(d) In case of a tunnelling barrier between ferromagnetic metal and paramagnetic semiconductor, the spin injection efficiency is 0.70. What is the
value of the polarization of the tunnelling conductivity at the interface?
(i) 0.3
(ii) 0.5
(iii) 0.7
(e) In case of a Schottky barrier between a ferromagnetic metal and
paramagnetic semiconductor interface, we obtain