What is Superconductivity?
26-08-2023
01:25 PM
1 min read
What’s in today’s article?
- Why in news?
- What is Superconductivity?
- News Summary: Why room temperature superconductivity remains science’s elusive Holy Grail
- Why the quest for a room-temperature superconductor?
- Why room temperature superconductivity remains elusive?
Why in news?
- Two new papers published recently have indicated the possibility of a room-temperature superconductor.
- Two South Korean researchers claimed that a lead-based compound they had developed had shown superconducting properties at room temperature, under normal pressure conditions.
What is Superconductivity?
- About
- Superconductivity refers to a state in which a material offers zero, or near-zero, resistance to electric current.
- So far, this phenomenon is observed in certain materials at very low temperatures, typically close to absolute zero (-273.15°C or 0 Kelvin).
- In superconductors, electrical resistance drops to virtually zero, allowing electric current to flow through them without any loss of energy due to resistance.
- Key characteristics
- Zero Resistance: In a superconductor, electrons can move through the material without encountering any resistance.
- Perfect Diamagnetism: Superconductors exhibit a strong repulsion of magnetic fields, a property known as perfect diamagnetism.
- When a superconductor is exposed to an external magnetic field, it expels the magnetic flux lines from its interior, effectively causing the magnetic field to be excluded from the material.
- Critical Temperature (Tc): Every superconductor has a critical temperature.
- Below this temperature, the material exhibits superconducting behaviour.
- Above the critical temperature, the material returns to its normal state with resistive behaviour.
- Meissner Effect: It is the expulsion of a magnetic field from the interior of a superconductor as it transitions into the superconducting state.
- This effect results in the material's ability to trap a magnetic field within its interior, preventing it from penetrating the material.
- Application
- A current is nothing but the movement of charged particles, electrons in most cases, in a particular direction.
- When the electrons move, they collide, and interact, with other atoms in the material.
- This creates resistance, which in turn involves loss of energy, mostly in the form of heat.
- In superconductors, electrical resistance drops to virtually zero. This property has numerous practical applications in various fields, including energy transmission, transportation, and scientific research.
- Superconducting materials show very interesting behaviour under magnetic field which allows the functioning of systems like the MRI scan machine and the superfast Maglev trains that float above the tracks.
- Materials to show superconducting properties
- The first material to have been discovered to show super conductive properties was Mercury, which becomes a superconductor at close to 270 degree Celsius below zero.
- Most of the other materials commonly used as superconductors are Lead, Aluminum, Tin, Niobium etc.
News Summary: Why room temperature Superconductivity remains science’s elusive Holy Grail
- The two new papers uploaded on the internet, by researchers from South Korea, state the creation of a material known as LK-99.
- As per them, this material can conduct superconductivity at room temperatures.
- According to South Korean researchers, LK-99, the new superconductor, can be synthesised through a baking process that involves combining the minerals lanarkite (Pb2SOâ‚…) and copper phosphide.
- The resulting material exhibits two essential characteristics of superconductivity even at normal air pressure and temperatures as high as 127 degrees Celsius.
- The researchers have put forward a plausible theory explaining how LK-99 could achieve room-temperature superconductivity.
- They have not yet provided definitive experimental evidence to support their claims.
Why the quest for a room-temperature superconductor?
- In superconductors, a quantum phenomenon causes electrons to pair up allowing them to move through the structure of the material with remarkable ease and near-zero electrical resistance and no loss of energy.
- But that happens only at very low temperatures, typically near absolute zero or minus 273.15 degrees Celsius, and extremely high pressure.
- To achieve these conditions, you require costly and complex cooling systems like liquid helium for superconductivity to happen. This limitation has restricted their widespread practical applications.
- A room-temperature superconductor would exhibit superconducting properties at temperatures that are easily attainable and sustainable with conventional cooling methods.
- This could lead to transformative advancements in various industries at low costs.
Why room temperature superconductivity remains elusive?
- Material, showing superconductivity at room temperature, are expected to be much more complex than the normal superconductors (at low temperatures).
- Hence, these are much more difficult to synthesize, and keep stable.
Q1) What is the Meissner Effect??
The Meissner effect, also known as the Meissner-Ochsenfeld effect, is a phenomenon in the field of superconductivity, which is a state of matter where certain materials can conduct electric current with zero electrical resistance. This effect was discovered by physicists Walther Meissner and Robert Ochsenfeld in 1933. When a material enters the superconducting state, it expels almost all magnetic fields from its interior, causing them to be excluded from the bulk of the material. This expulsion of magnetic fields is a hallmark of the Meissner effect. As a result, when a superconductor is placed in an external magnetic field, the magnetic field lines are pushed out of the material and form a "shielding" layer around its surface.
Q2) What is Diamagnetism?
Diamagnetism is a property of materials that causes them to create a weak magnetic field in the opposite direction when exposed to an external magnetic field. Unlike paramagnetic or ferromagnetic materials that are attracted to magnetic fields, diamagnetic materials are repelled by them.
Source: Why room temperature superconductivity remains science’s elusive Holy Grail | The Hindu | India Today