Cultural Project 1- Superconductors Molly Risko Xinyu Zhu Evonne Britton Shu Chen

Observation of Superconducotrs In 1911, a Dutch physicist from Linden University, Heike Kamerlingh Onnes first observed superconductors in mercury. He found that when he cooled the temperature of helium to 4 degrees Kelvin (-452F, -269C), which is the boiling point of helium, the electrical resistance of a mercury filament would suddenly disappear. Onnes realized that this might be a new state of Mercury, because of its extraordinary electrical properties. He defined this state as a “superconductive state”.electrical resistance This was when superconductors were first discovered.

What is a superconductor? Superconductors lose all electrical resistance when cooled to a specific temperature. This allows the materials to transmit electrical currents without losing any power, but having to keep the materials used at a cool temperature makes it impractical for larger, more powerful machines, such as computers, to use.

Another Discovery The second great milestone was in discovered in German researchers Walther Meissner and Robert Ochsenfeld founded another unique characteristic of superconductors called the diamagnetic property.

Diamagnetism and the Meissner Effect Diamagnetism is the property of an object to create a magnetic field opposite to an external magnetic field. This leads to a repulsive effect. Basically, the external field changes the orbital velocity of electrons. This phenomenon is nowadays called the Meissner effect.

Recent News Then, in the 1980’s cuprate superconductors were discovered. Cuprates operate at higher temperatures, but still not at practical, room temperature. The material that was discovered to be a cuprate was copper oxide. It was thought that the oxygen and copper atoms would group together in symmetrical units, which would mean the electrons, would behave symmetrically also, choosing different directions in which to spin. Instead they all chose the same direction- this is called broken symmetry. This choice represents a change in phase.

Summary and Societal Effects The article that our discovery was on was the asymmetric electron behavior discovered in high temperature superconductors. Researchers at Cornell University made this discovery. In the superconductor, copper oxide, the electrons randomly chose a preferred direction in which to spin. This led to the idea of broken symmetry. If scientists can get to the bottom of this broken symmetry, then that can lead to a breakthrough in using superconductors at higher temperatures. Knowing this about the electrons and their spinning directions will help scientists figure out if a material unit is symmetrical or of a broken symmetry. This will help determine if in fact the materials they use will be in a non- conducting or conducting state in order to carry out the process of conducting electricity successfully. The scientists discovered that these electrons can possibly lead to a world were we can conduct electricity without power loss. This would create a long–term, energy- saving electrical source. This would save people and countries billions of dollars, making electricity more affordable in homes, offices and factories.