A magnetic analog of the isotope effect in cuprates
Amit Keren, Faculty of Physics, Technion
19/04/2012 - 12:15
Resnick Building 209, room 210
Since the discovery of high temperature superconductivity in the cuprates, it has been speculated that their pairing mechanism is due to magnetic interactions. However, this was never demonstrated in the laboratory. Such a demonstration would require an experiment similar to the isotope effect in metallic superconductors, namely, a measurement of Tc versus the strength of the magnetic coupling J, with no other structural changes. We have done this experiment using the (CaxLa1-x)(Ba1.75-xLa0.25+x)Cu3Oy system with its 4 different families having different Tcmax, but identical structures. For each family, we measured the Néel
Temperature TN, the anisotropies of the magnetic interactions, the spin glass temperature Tg of underdoped samples, the carrier density n, the superconducting carrier density ns, and, of course, Tc from under to overdoped compounds. Our measurements allow us to demonstrate that Tc=cJns and more.