This blog post explores how superconductors address energy loss issues and what changes they could bring to our society and technology.
Modern science states that energy is conserved throughout the entire universe. However, energy useful to humanity often transforms into useless energy. In daily life, not all energy people use when performing work is actually utilized for that work. This is because some energy is converted into heat energy due to the resistance of objects. This is a thermodynamically spontaneous phenomenon, while the conversion of heat energy into other forms of energy is a non-spontaneous phenomenon. In other words, some of the energy that people perceive as useful is wasted each time it is used. This natural waste of energy profoundly impacts every aspect of our lives. Consequently, humanity has long sought ways to reduce energy loss and use energy more efficiently.
So, what if there were a material that could prevent this waste? For electrical energy specifically, such a material exists—one that eliminates energy loss. That material is a superconductor. A superconductor is a conductor that exhibits superconductivity below a specific temperature (called the critical temperature). Superconductivity is the phenomenon where a material’s electrical resistance drops to zero and the material becomes diamagnetic. Diamagnetism is the phenomenon where a material repels an internal magnetic field. If an object possesses diamagnetic properties, a magnetic field cannot penetrate its interior. Superconductors are classified into Type I and Type II superconductors. A Type I superconductor is one that completely prevents any magnetic field from penetrating its interior. A Type II superconductor is one that allows some magnetic field to penetrate its interior. In other words, a Type II superconductor is a material that maintains superconductivity without exhibiting perfect diamagnetism. Type I superconductors are mostly pure substances, while Type II superconductors are generally synthetic materials created as needed. Most technologies utilizing superconductors employ Type II superconductors.
How were superconductors discovered? Like many other discoveries, the discovery of superconductivity happened by chance. In 1911, Dutch physicist Heike Kamerlingh Onnes conducted experiments on the relationship between the temperature of solid mercury and its electrical resistance. Heike Kamerlingh Onnes discovered that mercury’s resistance decreased linearly with temperature as the temperature dropped. However, when the mercury’s temperature reached 4.2K, the resistance suddenly dropped to zero. This discovery caused a major shock in the physics community at the time and sparked a new understanding of the physical phenomena occurring at extremely low temperatures.
Following the first observation of superconductivity, in 1933, Fritz Walther Meißner and Robert Ochsenfeld discovered that Type I superconductors exhibit diamagnetic properties. This discovery provided a foundation for a deeper understanding of superconductors. Their finding marked a major turning point in superconductivity research and spurred active investigation into the potential commercial applications of superconductors. Subsequently, in 1950, Lev Landau and Vitaly Ginzburg published a theory explaining the properties of superconductors. Alexey Abrikosov predicted, based on this theory, that superconductors would be classified into two types. In 1962, the first commercial superconductor was developed. Since then, engineers have strived to develop superconductors exhibiting superconductivity at room temperature.
Type I superconductors are nearly impossible to apply commercially due to their properties. In contrast, Type II superconductors are applied in various fields. A representative example of superconducting applications is the superconducting electromagnet. An electromagnet is a magnet that becomes magnetized only when an electric current flows through it. Electromagnets are used in speakers and similar devices. Using a superconductor, which has zero resistance, to make an electromagnet can prevent power waste during its operation. Superconductors are also used in circuits. Circuits utilizing superconductors operate faster than those without them. Faster circuit operation not only shortens experimental times when using the circuit but also enables the development of faster electronic devices.
If a superconductor exhibiting superconductivity at room temperature is developed, that material could be utilized in various fields such as power transmission lines, capacitors, transformers, magnetic levitation trains, and motors. Superconducting wires eliminate electrical energy loss during power transmission. Eliminating unnecessary energy loss means less power needs to be generated, preventing resource waste.
Maglev trains using superconductors can travel at ultra-high speeds. This will contribute to the advancement of transportation. Currently, engineers have raised the critical temperature of superconductors to 52K, and research continues. The superconductor, discovered by accident by Heike Kamerlingh Onnes, has also left a significant mark in the history of science for modern society facing energy crises.
Since the discovery of superconductors, they have profoundly influenced not only physics but also diverse fields like electrical engineering and materials science. Superconductors are no longer merely objects of physical curiosity; they have become important technological tools with practical application potential. Moreover, they show great potential to significantly contribute to societal development. In today’s world, where the reckless use of limited resources is problematic, the development of superconductors usable at room temperature is considered crucial. If engineers develop materials exhibiting superconductivity at room temperature, humanity will take another step forward in its evolution. As the commercial applications of superconductors expand, we will be able to use energy in more efficient and sustainable ways. This will play a crucial role in solving many of the problems facing humanity, particularly those related to energy and the environment.
