Superconductors are superior to conductors in their ability to transmit electrical energy without energy wastage in the form of heat as they offer practically no resistance to flow of electricity. Superconductors could thus be deemed suitable for cost effective green power production rather than the conventional copper and silver-based conductors.
Proffesor Yoram Dagan from Tel Aviv University (Credit: American Friends of Tel Aviv University (AFTAU))
However, preparing superconductors is a challenge because materials acquire the superconducting property only at very high temperatures. Controlling this critical temperature at which transition to superconductivity takes place is tricky.
Professor Yoram Dagan from the department of physics and center for nanoscience and nanotechnology at the Tel Aviv University has developed a novel method to manipulate the critical temperature of superconductors using light.
The critical temperature of superconductors has previously been altered by addition and removal of oxygen ions and chemical doping. Professor Dagan’s method is simpler than existing methods. It involves placing a single organic molecule thick layer on top of a superconducting film measuring 50 nm in thickness. Irradiating the molecules with light resulted in the molecules changing their size and shape and subsequently altering the superconductor properties, especially the critical temperature. Totally three molecules were tested in the experiment. The first molecule was found to raise the critical temperature of the superconducting film on exposure to light. The second molecule raised the critical temperature to a maximum when exposed to ultraviolet light but lowered the critical temperature on exposure to visible light. The third molecule was found to raise the critical temperature of the superconducting film by just switching the light on and lowered the critical temperature when the light was switched off. This can be deemed as a knob for manipulating the temperature of superconducting materials.