Ten years after it was theorized, scientists in China have discovered a new type of superconductor, the superhydride CaH.6 They synthesized . There are several ways that physicists hope could lead to practical, room-temperature superconductors. Among them, one of the most productive includes hydrogen-rich binary compounds containing rare earth or actinide elements. One such compound, the lanthanum superhydride, has been shown to be superconducting at temperatures up to 260 K, but only at pressures greater than 170 gpa.
What is Superconductivity?
Spericonductivity is the complete loss of electrical resistance in various solids when cooled below a characteristic temperature. This temperature, called the transition temperature, varies for different materials, but is usually below 20 K (-253 °C).
in magnets of superconductors There are certain conditions for its use. These materials work in environments with strong magnetic fields above a certain critical value.
It is also limited in that it causes a superconductor to return to its normal or non-superconducting state, even though the material is kept well below its transition temperature.
The suggested uses for superconducting materials are diverse. These include medical magnetic imaging devices, magnetic energy storage systems, motors, generators, transformers, computer parts, and very sensitive devices for measuring magnetic fields, voltages or currents. The main advantages of devices made of superconductors are low power dissipation, high speed operation and high sensitivity.
Discovery of Superconductivity
Dutch physicist discovered superconductivity in 1911. Heike Kamerlingh Onnes discovered by; He was awarded the Nobel Prize in Physics in 1913 for his low temperature research. Kamerlingh Onnes found that the electrical resistance of a mercury wire suddenly disappears when cooled below about 4 K (-269 °C); absolute zero is 0 K, the temperature at which all matter loses its disorder. A short time later, research continued by passing a sufficiently large current through a superconducting material. He discovered that this material could also be returned to its normal (i.e. non-superconducting) state if a sufficiently strong magnetic field was applied.
If we go back to our article;
Now, Liang Ma of Jilin University in China and colleagues have expanded the research by synthesizing a new type of superhydride that contains alkaline earth metal instead of rare earth metal or actinide.
The researchers found that the new material, clathrate calcium hydride (CaH6 ) synthesis opens the door to a currently little-researched class of superconductors.
CaH6Its structure and superconducting properties were first predicted in 2012.
However, subsequent attempts were made to synthesize the compound. It failed to overcome barriers such as high reactivity between calcium and hydrogen that, when combined at low pressures, could result in hydrides with low hydrogen content.
In their new study, Ma and colleagues address this issue as a hydrogen source, such as ammonia borane (BH).3NH3 ) were used to solve it. This allowed them to synthesize the compound by direct reaction between calcium and hydrogen at high temperature and pressure.
In the team's experiments, the synthesized CaH6 , exhibited superconducting properties very close to theoretical predictions and reached a critical temperature of 172 K at 215 gpa.
This temperature is lower than the record set by the lanthanum superhydride at a similar unrealistic pressure. However, the researchers expect that experiments with other alkaline earth metal superhydrides will result in superconductivity at more favorable pressures and room temperature.