Near-ambient superconductivity

Breaking News: near-ambient superconductivity

A team of researchers led by Professor Ranga Dias from the University of Rochester has created a superconducting material that operates at low enough temperatures and pressures to be used in practical applications. The material, nitrogen-doped lutetium hydride (NDLH), exhibits superconductivity at 69 degrees Fahrenheit and 10 kilobars of pressure. The achievement brings the possibility of ambient superconductivity and applied technologies. The work was published in Nature.

Superconducting materials have two key properties: electrical resistance vanishes, and magnetic fields that are expelled pass around the superconducting material. Such materials could enable power grids that transmit electricity without losing energy, frictionless, levitating high-speed trains, affordable medical imaging and scanning techniques, faster, more efficient electronics for digital logic and memory device technology, and tokamak machines that use magnetic fields to confine plasmas to produce fusion as a source of unlimited power.

The researchers from the University of Rochester used rare earth metal lutetium and nitrogen to create a cage-like lattice structure that enables superconductivity to occur at lower pressure. The resulting compound, lutetium-nitrogen-hydrogen, was initially blue and turned pink at the onset of superconductivity, and then bright red in a non-superconducting metallic state when compressed. The achievement was made possible by stabilizing the structure of superconducting materials with nitrogen and carbon, thereby reducing the pressure required for superconductivity to occur.

Superconducting material lutetium hydride
Lutetium hydride shows near-ambient superconductivity.

The discovery has broad implications for superconducting consumer electronics, energy transfer lines, transportation, and magnetic confinement for fusion.

Superconducting materials

When cooled below a certain critical temperature, superconducting materials can conduct electricity without any resistance. This phenomenon was first discovered in 1911 by Dutch physicist Heike Kamerlingh Onnes, who found that the resistance of mercury dropped to zero at a temperature of 4.2 Kelvin (-268.8 ºC).

Since then, many other superconducting materials have been discovered, including metals, alloys, ceramics, and even some organic materials. The critical temperature at which a material becomes a superconductor varies widely, with some materials only becoming superconducting at temperatures close to absolute zero, while others at much higher temperatures.

The potential applications of superconducting materials are vast and include:

  1. High-speed computing: Superconducting materials can be used to create ultrafast computers that can process information at unprecedented speeds.
  2. Magnetic levitation: Superconductors can be used to create powerful magnetic fields, which can be used to levitate trains, ships, and other objects without any friction or energy loss.
  3. Medical imaging: Superconducting magnets are used in MRI machines to create high-resolution images of internal body structures.
  4. Energy storage: Superconducting materials can be used to create high-capacity energy storage systems, which could revolutionize the way we store and distribute electricity.
  5. Particle accelerators: Superconducting magnets are used in particle accelerators to create intense magnetic fields, which are necessary to accelerate particles to very high speeds.
  6. Superconducting motors and generators: Superconductors can be used to create highly efficient electric motors and generators that produce no energy loss due to resistance.

Overall, superconducting materials have the potential to revolutionize a wide range of industries and technologies, leading to more efficient and powerful devices and systems.

History of superconductive materials

The history of superconducting materials dates back to 1911 when the Dutch physicist Heike Kamerlingh Onnes discovered the phenomenon of superconductivity in mercury. Onnes observed that when mercury was cooled to a temperature of 4.2 Kelvin (-268.8 ºC), its electrical resistance suddenly dropped to zero and it could conduct electricity with 100% efficiency.

Onnes’ discovery sparked a wave of research into superconducting materials, with scientists trying to understand the mechanism behind the phenomenon and to find other materials that exhibited the same behavior. In the 1930s, scientists discovered that certain metals, such as lead and tin, could also exhibit superconductivity at very low temperatures.

In the 1950s and 1960s, the discovery of new superconducting materials, including alloys and intermetallic compounds, led to the development of practical applications such as superconducting magnets for use in medical imaging and particle accelerators.

In 1986, two IBM scientists, Georg Bednorz and K. Alex Müller, made a groundbreaking discovery that revolutionized the field of superconductivity. They discovered that certain copper oxide compounds could exhibit superconductivity at much higher temperatures than had previously been thought possible, up to around 90 Kelvin (-183 ºC). This discovery led to the development of high-temperature superconductors, which have the potential to be used in a wide range of practical applications, from power transmission to levitating trains.

Since then, researchers have continued to discover new superconducting materials and to explore their potential applications. In 2001, scientists discovered a class of materials known as iron-based superconductors, which exhibit superconductivity at temperatures of up to around 55 Kelvin (-218 ºC).

Properties of superconducting materials

Superconducting materials possess a unique set of properties that distinguish them from normal conducting materials. Some of the key properties of superconducting materials are:

  1. Zero electrical resistance: The most notable property of superconductors is that they have zero electrical resistance at low temperatures. When an electrical current flows through a superconductor, it encounters no resistance and can flow indefinitely without losing any energy.
  2. Meissner Effect: Superconductors also exhibit the Meissner effect, which is the complete expulsion of magnetic fields from their interior. This property makes them ideal for use in magnetic levitation and MRI machines.
  3. Critical temperature: Each superconductor has a critical temperature below which it can exhibit zero electrical resistance. This critical temperature varies depending on the material and can range from a few degrees Kelvin to above room temperature.
  4. Critical magnetic field: Superconductors have a critical magnetic field above which they lose their superconducting properties. This critical magnetic field is different for different superconducting materials.
  5. High current densities: Superconductors can carry very high current densities without any loss of energy, making them ideal for use in power transmission and storage.
  6. Superconducting phase transitions: Superconductors undergo phase transitions as the temperature or magnetic field is varied. In particular, they exhibit a second-order phase transition at their critical temperature, which is accompanied by a sudden change in their electrical properties.
  7. Type I and Type II superconductors: Superconductors are classified into two types based on their response to an applied magnetic field. Type I superconductors expel the magnetic field completely, while Type II superconductors allow the magnetic field to penetrate in the form of quantized vortices.

The unique properties of superconducting materials make them extremely useful for a wide range of applications, including power transmission, magnetic levitation, MRI machines, and particle accelerators.

Current state of the field:

The field of superconducting materials research is currently focused on discovering new materials that can exhibit superconductivity at higher temperatures, which would allow for more practical applications. The most promising superconducting materials being developed today include:

  1. High-temperature superconductors (HTS): These materials are typically made of copper, oxygen, and a rare earth element, and can achieve superconductivity at temperatures up to -135 ºC, much higher than traditional superconductors. They have been used in a variety of applications, including MRI machines, power transmission, and particle accelerators.
  2. Iron-based superconductors (FeSC): These materials were discovered in 2008 and have the potential to achieve even higher critical temperatures than HTS. They are made of iron, arsenic, and other elements, and are currently being studied for use in power generation and magnetic levitation trains.
  3. Organic superconductors: These materials are made of organic compounds and have the advantage of being flexible and lightweight. They have potential applications in electronics and sensors.

Recent advancements in the field of superconducting materials include the discovery of new HTS materials, such as H3S, which can achieve superconductivity at a record-breaking temperature of -70 ºC under high pressure. Another breakthrough is the development of FeSC materials with improved properties, such as LaO₁₋ₓFₓFeAs, which can achieve superconductivity at a temperature of -26 ºC.

Researchers are also exploring the use of superconducting materials in new applications, such as quantum computing, where they can be used to create qubits with long coherence times, and in energy storage, where they can be used to create highly efficient batteries.

Potential applications of superconducting materials

Superconducting materials have the potential to revolutionize a wide range of industries due to their unique properties. Here are some of the most promising applications:

  1. Power grids: Superconducting materials can be used to make highly efficient power transmission cables that can carry more electricity over longer distances without loss. This could help to improve the efficiency of the electrical grid and reduce energy waste.
  2. Transportation: Superconducting materials can be used to create powerful, lightweight magnets for use in high-speed trains and levitating trains. This could help to reduce transportation times and increase efficiency.
  3. Medical imaging: Superconducting materials can be used to create powerful magnets for use in MRI machines, which can provide detailed images of the body’s internal organs and tissues. This could help to improve the accuracy of medical diagnoses and treatments.
  4. Quantum computing: Superconducting materials can be used to create qubits, which are the building blocks of quantum computers. This could help to revolutionize computing by enabling the development of faster, more powerful computers.
  5. Particle accelerators: Superconducting materials can be used to create powerful magnets for use in particle accelerators, which are used to study the fundamental properties of matter. This could help to advance our understanding of the universe and lead to new discoveries in physics.

Recent advancements in superconducting materials have made these potential applications more feasible than ever before. For example, the development of high-temperature superconductors has made it possible to create superconducting materials that can operate at higher temperatures, which could make them more practical for use in a wider range of applications. Additionally, the use of advanced manufacturing techniques, such as 3D printing, has made it possible to create complex shapes and structures with superconducting materials, which could open up new possibilities for their use.

Challenges and limitations

Although superconducting materials have enormous potential, there are still several challenges and limitations that need to be addressed.

One of the main challenges is the difficulty of developing high-temperature superconducting materials that can operate at temperatures that are practical for commercial use. Another challenge is the high cost of producing superconducting materials, which can limit their widespread adoption.

There are also technical limitations, such as the fact that superconducting materials are typically brittle and can be difficult to work with. Additionally, there are challenges related to creating large-scale applications of superconducting materials, such as the need to develop new cooling technologies that can efficiently cool large superconducting systems.

To address these challenges, researchers are working on developing new materials with higher superconducting temperatures and greater durability. They are also exploring new manufacturing techniques that can reduce the cost of producing superconducting materials.

In terms of technical limitations, researchers are working on developing new fabrication techniques that can produce superconducting materials with improved mechanical properties. They are also exploring new cooling technologies, such as cryocoolers and pulse-tube refrigeration, that can cool large-scale superconducting systems.

In conclusion, superconducting materials have the potential to revolutionize many areas of technology, including energy, transportation, and healthcare. With their ability to conduct electricity with zero resistance, superconductors can make power grids more efficient, improve the performance of transportation systems, and enhance the quality of medical imaging.

Despite the many advancements made in the field, there are still significant challenges to overcome, including high costs, materials limitations, and technical difficulties in scaling up production. However, with ongoing research and development, there is hope that these challenges can be overcome, leading to even greater advancements in the use of superconducting materials. Overall, superconducting materials represent a promising area of research that has the potential to transform the way we live and work.

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