SHORT NOTE ON SUPERCONDUCTOR

Author: Ashraful Azam

*
Dept of Electrical and Electronic and Engineering, Islamic University of Technology, Bangladesh
Email: ashrafulazam@iut-dhaka.edu

Abstract—The following article provides an overview of superconduct at significantly higher temperatures, making
historical aspects, current work in progress as well as the future them more practical for various applications.[4]. Figure 1
applications of superconductors. The discovery of such
materials has not only expanded our understanding of the A relatively more recent breakthrough includes the discovery
quantum world but has also led to plethora of technological
advancements with implications in diverse fields.
of Iron-based superconductors, discovered by a team led by
Hideo Hosono in 2008, represented another class of high-
I. INTRODUCTION temperature superconductors, sparking new research
avenues. The superconductivity of these materials occurred
Superconductors, a special class of materials which are by doping a parent antiferromagnetic metal or Pauli
able to carry electrical current with absolute efficiency and the
paramagnetic metal with either electrons or holes.[5]
ability to defy magnetic fields, have been the focus of
scientific inquiry and technological exploration for over a III. RECENT BREAKTHROUGH AND APPLICATIONS
century. From the pioneering discovery of superconductivity
by Heike Kamerlingh Onnes in 1911 to the emergence of Recent years have witnessed a groundbreaking breakthrough
high-temperature superconductors in the late 20th century, that promises to take superconductivity to new heights and
these materials have captivated the imaginations of physicists open doors to transformative applications. For decades, one
and engineers, fundamentally altering our understanding of of the holy grails of superconductivity research has been the
condensed matter physics and offering transformative quest for materials that can superconduct at or near room
possibilities across diverse technological domains. This temperature, eliminating the need for extremely low
scholarly exploration delves into the multifaceted world of temperatures to maintain their extraordinary properties.
superconductors, delving into the rich historical context of
their discovery, the intricate quantum mechanical principles In 2020, researchers made a profound leap toward this goal
underpinning their behavior, and the far-reaching implications when they announced the discovery of a hydrogen sulfide
for applications ranging from power transmission and medical compound that exhibited superconductivity at an
diagnostics to quantum information processing. astonishingly high temperature—roughly 15 degrees Celsius
II. HISTORY (59 degrees Fahrenheit). This breakthrough was achieved
under extreme pressures, which are typically not practical for
The phenomenon of superconductivity was first discovered everyday use. However, the implications are profound. It
by the Dutch physicist Heike Kamerlingh Onnes in 1911. He demonstrated that room-temperature superconductors could
observed that mercury's electrical resistance dropped to zero exist and offered hope for finding materials that can maintain
when it was cooled to temperatures close to absolute superconductivity at more accessible conditions.[6]
zero(cryogenic.[1] The next great milestone in understanding
how matter behaves at extreme cold temperatures occurred in Researchers continued to explore and discover new high-
1933. ritz and Heinz London, in collaboration with Walther temperature superconductors, which are materials that can
Meissner and Robert Ochsenfeld, discovered that exhibit superconductivity at relatively higher temperatures
superconductors expel magnetic fields from their interiors, a compared to conventional superconductors. This has led to
phenomenon known as the Meissner-Ochsenfeld effect. This advancements in practical applications, such as more
marked a crucial development in understanding efficient power transmission and the development of new
superconductivity.[2] Later on the BCS theory, proposed by materials with higher critical temperatures.
John Bardeen, Leon Cooper, and Robert Schrieffer in 1957, Conventional power transmission lines, made of materials
has been highly successful in explaining the properties of like copper or aluminum, experience electrical resistance that
conventional superconductors. It provides a comprehensive causes energy losses in the form of heat. Superconducting
understanding of how attractive electron interactions power cables, on the other hand, exhibit zero electrical
mediated by lattice vibrations can lead to the remarkable resistance. This means that when electrical current flows
properties of superconductors, including zero resistance, the through a superconducting cable, there are no energy losses
expulsion of magnetic fields, and the energy gap. While the due to resistance, resulting in significantly more efficient
BCS theory specifically applies to low-temperature power transmission. Superconductors can carry extremely
superconductors, its principles have influenced the high current densities without resistance or heating. This high
understanding of various superconducting materials, current-carrying capacity allows for the transmission of a
including high-temperature superconductors. [3] The large amount of power through relatively small-diameter
discovery of high-temperature superconductors (HTS) by cables. As a result, power lines can be designed with a smaller
Georg Bednorz and K. Alex Müller in 1986 marked a cross-section, reducing the overall infrastructure and land use
revolutionary development. HTS materials could required for transmission.[7] [8] Figure 2

978-1-6654-9045-0/22/$31.00 ©2022 IEEE

Magnetic levitation (Maglev) trains, which already use Two recent articles that claim to demonstrate the fabrication
superconducting magnets for levitation, could become even of a novel superconductor that operates at normal temperature
more efficient. High-speed and energy-efficient and ambient pressure have piqued the interest of many
transportation systems, such as Maglev trains, could become researchers. Scientists in Korea claimed to have synthesised
more practical and widespread. In Maglev, superconducting LK-99, an innovative material that would rank among the
magnets suspend a train car above a U-shaped concrete greatest advances in physics in recent memory. [12]
guideway. Like ordinary magnets, these magnets repel one
another when matching poles face each other. The used
magnets are superconducting, which implies that they can CONCLUSION
produce magnetic fields up to ten times stronger than regular
electromagnets—strong enough to suspend and move a While the discovery of room-temperature superconductivity
train—when chilled to less than 450 degrees Fahrenheit is a monumental achievement, several challenges lie ahead.
below zero. Researchers must find or engineer materials that can exhibit
these properties at manageable pressures and conditions.
The Maglev guideway's concrete walls contain basic metallic Additionally, the scalability, stability, and cost-effectiveness
loops that are in contact with these magnetic fields. Because of such materials need to be addressed before widespread
the loops are composed of conductive materials, such as commercial applications can be realized. As researchers
aluminum, a magnetic field applied to them will cause an continue to push the boundaries of what is possible in
electric current to flow, which in turn will produce another superconductivity, the future may hold an era where the
magnetic field. remarkable properties of superconductors are accessible at
The trains are highly efficient, as they generate strong room temperature, revolutionizing numerous technological
magnetic fields without the need for a continuous power domains.
supply to maintain the levitation. Once the superconducting
magnets are energized and reach their critical temperature
(below which they become superconducting), they can FIGURES
maintain the magnetic field without consuming additional
energy. This leads to low energy consumption during
operation. Figure 3

Another broad application of superconductivity is in the

domain of image processing. Room-temperature
superconductors would eliminate the need for expensive and
complex cryogenic cooling systems in these devices, making
MRI technology more accessible and cost-effective. The
primary application of superconductors in MRI machines is
in the creation of the main magnetic field. Superconducting
coils made from superconducting materials, typically
niobium-titanium (NbTi) or niobium-tin (Nb3Sn), generate a
strong, stable magnetic field. Because these materials can
maintain superconductivity at very low temperatures, MRI
machines are equipped with cryogenic cooling systems to Figure 1-A timeline for critical temperature of superconductor
keep the superconducting magnets at the required
temperature (typically around -269°C or -452°F). This allows
for the generation of extremely high magnetic field strengths,
which directly correlate with improved image quality in MRI
scans. High-field MRI machines can provide clearer and
more detailed images, making them valuable for diagnosing
various medical conditions. [9] Figure 4

Condensed-matter physicists and material scientists have

been attempting to determine ways to increase a given
material's superconductivity in recent years. This includes the
substance K3C60, an organic superconductor that, when
exposed to mid-infrared laser pulses, has been discovered to
reach a phase characterised by zero resistance. [10]

Superconductors can be utilized in quantum computing

through a technology called superconducting qubits. Qubits
are the fundamental building blocks of quantum computers,
and they can exist in multiple states simultaneously, thanks Figure 2-Superconducting cable
to the principles of quantum mechanics. [11]
 [5] Y. Kamihara, T. Watanabe, M. Hirano, and H. Hosono, ‘Iron-
Based Layered Superconductor La[O1-xFx]FeAs (x = 0.05−0.12)
with Tc = 26 K’, J Am Chem Soc, vol. 130, no. 11, pp. 3296–
3297, Mar. 2008, doi: 10.1021/ja800073m.
[6] A. P. Durajski and R. Szczęśniak, ‘First-principles study of
superconducting hydrogen sulfide at pressure up to 500 GPa’, Sci
Rep, vol. 7, no. 1, p. 4473, 2017, doi: 10.1038/s41598-017-04714-
5.
[7] H. Thomas, A. Marian, A. Chervyakov, S. Stückrad, D. Salmieri,
and C. Rubbia, ‘Superconducting transmission lines –
Sustainable electric energy transfer with higher public
acceptance?’, Renewable and Sustainable Energy Reviews, vol.
55, pp. 59–72, 2016, doi:
https://doi.org/10.1016/j.rser.2015.10.041.
[8] H. Jones, ‘Superconductors in the transmission of electricity and
networks’, Energy Policy, vol. 36, no. 12, pp. 4342–4345, 2008,
doi: https://doi.org/10.1016/j.enpol.2008.09.063.
[9] Y. Lvovsky and P. Jarvis, ‘Superconducting Systems for MRI—
Figure 3-Maglev Train Present Solutions and New Trends’, Applied Superconductivity,
IEEE Transactions on, vol. 15(2), pp. 1317–1325, Jul. 2005, doi:
10.1109/TASC.2005.849580.
[10] R.-S. Wang, D. Peng, L.-N. Zong, Z.-W. Zhu, and X.-J. Chen,
‘Full set of superconducting parameters of K3C60’, Carbon N Y,
vol. 202, pp. 325–335, 2023, doi:
https://doi.org/10.1016/j.carbon.2022.10.076.
[11] S. Bravyi, O. Dial, J. M. Gambetta, D. Gil, and Z. Nazario, ‘The
future of quantum computing with superconducting qubits’, J
Appl Phys, vol. 132, no. 16, p. 160902, Oct. 2022, doi:
10.1063/5.0082975.
[12] I. Timokhin, C. Chen, Q. Yang, and A. Mishchenko, ‘Synthesis
and characterisation of LK-99’, arXiv preprint arXiv:2308.03823,
2023.

Figure 4-Typical cross section of MRI machine

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