Chapter 8
Terahertz Spintronics
8.1 Introduction
The terahertz region occupies the border between the microwave and infrared regions
of the electromagnetic spectrum. This region of the electromagnetic spectrum is
known as the ‘terahertz gap’. Electronics dominates the instrumentation and technology below the THz gap whereas photonic dominates the paradigm, which is above
the gap. The convergence between optics and electronics takes place in the THz gap
(loosely defined frequency range 0.3–30 THz). Now a day, the THz region of the
electromagnetic spectrum is a thrust area for research in physics, chemistry, biology,
materials science and medicine (Lee 2009). Despite of some remarkable achievements, there is paucity of devices for the generation, modulation and the detection of
THz frequencies. New techniques and technologies are needed for the development of
new devices in this area. In this direction, terahertz spintronics can play a pivotal role
towards generation and controlling of THz waves utilizing magnetic materials. In this
chapter, we will discuss the necessity of terahertz science, its importance in science
and technology and finally some spin-dependent phenomena in spintronics structures in the THz range. The chapter will also illustrate different types of spintronic
terahertz emitter.
8.2 What Is Terahertz Radiation?
Terahertz radiations are not visible to human eye but we can feel it since a part its
spectrum is shared with far-infrared radiation (see Fig. 8.1). Their impact on human
body is not harmful as they are low energy radiations. As a result, it does not pose
any ionization hazard for biological tissues. Commonly used parameters at 1 THz
can be summarized as follows:
Frequency (ν): = 1 Terahertz = 10
3 Gigahertz.
Angular frequency (ω =2π ν): 6.28 Terahertz.
© Springer Nature Singapore Pte Ltd. 2021
P. Dey and J. N. Roy, Spintronics,
https://doi.org/10.1007/978-981-16-0069-2_8
185
Terahertz Spintronics
8.1 Introduction
The terahertz region occupies the border between the microwave and infrared regions
of the electromagnetic spectrum. This region of the electromagnetic spectrum is
known as the ‘terahertz gap’. Electronics dominates the instrumentation and technology below the THz gap whereas photonic dominates the paradigm, which is above
the gap. The convergence between optics and electronics takes place in the THz gap
(loosely defined frequency range 0.3–30 THz). Now a day, the THz region of the
electromagnetic spectrum is a thrust area for research in physics, chemistry, biology,
materials science and medicine (Lee 2009). Despite of some remarkable achievements, there is paucity of devices for the generation, modulation and the detection of
THz frequencies. New techniques and technologies are needed for the development of
new devices in this area. In this direction, terahertz spintronics can play a pivotal role
towards generation and controlling of THz waves utilizing magnetic materials. In this
chapter, we will discuss the necessity of terahertz science, its importance in science
and technology and finally some spin-dependent phenomena in spintronics structures in the THz range. The chapter will also illustrate different types of spintronic
terahertz emitter.
8.2 What Is Terahertz Radiation?
Terahertz radiations are not visible to human eye but we can feel it since a part its
spectrum is shared with far-infrared radiation (see Fig. 8.1). Their impact on human
body is not harmful as they are low energy radiations. As a result, it does not pose
any ionization hazard for biological tissues. Commonly used parameters at 1 THz
can be summarized as follows:
Frequency (ν): = 1 Terahertz = 10
3 Gigahertz.
Angular frequency (ω =2π ν): 6.28 Terahertz.
© Springer Nature Singapore Pte Ltd. 2021
P. Dey and J. N. Roy, Spintronics,
https://doi.org/10.1007/978-981-16-0069-2_8
185