Preface
vii
band gap in ferromagnetic materials is analysed. It also gives the outline of
different emerging branches of spintronics.
• Chapter 2 lays the foundation of spintronics. Almost all the basic phenomena
contributing to fascinating field of spintronics are discussed. These include some
important notions, such as spin polarization, spin filter effect, spin injection, spin
accumulation, spin relaxation, spin extraction etc. Passive spintronic devices, such
as spin valves, are described in this chapter. This chapter also presents different
kinds of spin relaxation mechanisms, such as the D’yakonov-Perel’, the ElliottYafet, the Bir-Aronov-Pikus and hyperfine interactions with nuclear spins. Field
and heat-driven spintronics effect, i.e., spin Hall effect, and Seebeck effect are
also presented.
• Chapter 3 is devoted to discuss the most fundamental effect in spintronics, i.e.,
giant magnetoresistance (GMR). Different kinds of magnetoresistance and qualitative explanation of physical origin of GMR are explained. Spin-dependent and
spin-flip scattering of electrons are described. Magnetoresistance theory based on
resistor network theory of GMR is also discussed.
• Chapter 4 deals with the concept of tunnelling magnetoresistance, magnetic junctions and magnetic tunnel junction (MTJ). Quantum mechanical tunnelling of
conduction electrons, which is at the origin of MTJ, is discussed in the light of A
transfer matrix model. The Jullière formula is also explained elaborately.
• Chapter 5 emphasizes on spin transfer torque (STT). This chapter talks about spin
transfer torque-driven magnetization dynamics and the possible applications of
spin transfer torques in spintronic devices.
• Chapter 6 describes magnetic domain walls (DW) motion. Ratchet effect in
magnetic DW motion is discussed. This chapter also gives the idea of currentdriven DW motion.
• Chapter 7 deals with the emerging field of spintronics, i.e., optospintronics.
The ultrafast manipulation of magnetic order by femtosecond lasers, as external
stimuli, is discussed in this chapter. Special emphasis is given onultrafast optical
controlling of magnetic states of antiferromagnet, i.e., antiferromagnetic optospintronics. Spin–photon interaction, Faraday effect and inverse Faraday effect are
presented. Outline of different types of all-optical spintronic switching is also
given in this chapter.
• Chapter 8 presents one more promising branch of spintronics, i.e., terahertz spintronics, which bears novel application in THz range. Principle of operation of
spintronic terahertz emitter and choice of materials for spintronic emitters are
discussed in this chapter. Terahertz writing of an antiferromagnetic magnetic
memory device is also discussed.
• Chapter 9 gives brief outline of one emerging branch of spintronics i.e.,
Semiconductor spintronics.
• Chapter 10 emphasizes on application side of spin-based devices. This chapter
discusses severalmodern spintronics devices that include GMR read head of
modern hard disk drive, MRAM, position sensor, biosensor, magnetic field sensor,
three terminal magnetic memory devices, spin FET etc.
vii
band gap in ferromagnetic materials is analysed. It also gives the outline of
different emerging branches of spintronics.
• Chapter 2 lays the foundation of spintronics. Almost all the basic phenomena
contributing to fascinating field of spintronics are discussed. These include some
important notions, such as spin polarization, spin filter effect, spin injection, spin
accumulation, spin relaxation, spin extraction etc. Passive spintronic devices, such
as spin valves, are described in this chapter. This chapter also presents different
kinds of spin relaxation mechanisms, such as the D’yakonov-Perel’, the ElliottYafet, the Bir-Aronov-Pikus and hyperfine interactions with nuclear spins. Field
and heat-driven spintronics effect, i.e., spin Hall effect, and Seebeck effect are
also presented.
• Chapter 3 is devoted to discuss the most fundamental effect in spintronics, i.e.,
giant magnetoresistance (GMR). Different kinds of magnetoresistance and qualitative explanation of physical origin of GMR are explained. Spin-dependent and
spin-flip scattering of electrons are described. Magnetoresistance theory based on
resistor network theory of GMR is also discussed.
• Chapter 4 deals with the concept of tunnelling magnetoresistance, magnetic junctions and magnetic tunnel junction (MTJ). Quantum mechanical tunnelling of
conduction electrons, which is at the origin of MTJ, is discussed in the light of A
transfer matrix model. The Jullière formula is also explained elaborately.
• Chapter 5 emphasizes on spin transfer torque (STT). This chapter talks about spin
transfer torque-driven magnetization dynamics and the possible applications of
spin transfer torques in spintronic devices.
• Chapter 6 describes magnetic domain walls (DW) motion. Ratchet effect in
magnetic DW motion is discussed. This chapter also gives the idea of currentdriven DW motion.
• Chapter 7 deals with the emerging field of spintronics, i.e., optospintronics.
The ultrafast manipulation of magnetic order by femtosecond lasers, as external
stimuli, is discussed in this chapter. Special emphasis is given onultrafast optical
controlling of magnetic states of antiferromagnet, i.e., antiferromagnetic optospintronics. Spin–photon interaction, Faraday effect and inverse Faraday effect are
presented. Outline of different types of all-optical spintronic switching is also
given in this chapter.
• Chapter 8 presents one more promising branch of spintronics, i.e., terahertz spintronics, which bears novel application in THz range. Principle of operation of
spintronic terahertz emitter and choice of materials for spintronic emitters are
discussed in this chapter. Terahertz writing of an antiferromagnetic magnetic
memory device is also discussed.
• Chapter 9 gives brief outline of one emerging branch of spintronics i.e.,
Semiconductor spintronics.
• Chapter 10 emphasizes on application side of spin-based devices. This chapter
discusses severalmodern spintronics devices that include GMR read head of
modern hard disk drive, MRAM, position sensor, biosensor, magnetic field sensor,
three terminal magnetic memory devices, spin FET etc.