What Is a High-Temperature Superconductor?

A high temperature superconductor (HTS) is a material that demonstrates superconducting electrical properties above the liquid state temperature of helium. This temperature range, from about -452° to -454° Fahrenheit (-269° to -270° Celsius) was believed to be the theoretical limit for superconductivity. In 1986, however, US researchers Karl Muller and Johannes Bednorz discovered a group of high-temperature superconductor compounds based on copper. These cuprates, such as yttrium barium copper oxide, YBCO₇, variations on lanthanum strontium copper oxide, LSCO, and mercury copper oxide, HgCuO, exhibited superconductivity at temperatures as high as -256° Fahrenheit (-160° Celsius).

The discovery by Muller and Bednorz led to the awarding of the Nobel Prize in physics in 1987 to both researchers, but the field continued to evolve. Ongoing study in 2008 produced a new class of compounds that exhibited superconductivity, based on the elements of iron and arsenic, such as lanthanum oxide iron arsenic, LaOFeAs. It was first demonstrated as a high-temperature superconductor by Hideo Hosono, a materials science researcher in Japan, at a temperature range of -366° Fahrenheit (-221° Celsius). Other rare elements mixed in with iron, such as cerium, samarium and neodymium created new compounds that also demonstrated superconductive properties. The record as of 2009 for a high-temperature superconductor was achieved with a compound made from thallium, mercury, copper, barium, calcium, strontium and oxygen combined, which demonstrates superconductivity at -211° Fahrenheit (-135° Celsius).

The focus of the field of high-temperature superconductor research as of 2011 has been materials science engineering of better compounds. When temperatures of -211° Fahrenheit (-135° Celsius) were reached for superconducting materials, this allowed their qualities to be examined in the presence of liquid nitrogen. Since liquid nitrogen is a common and stable component of many laboratory environments and exists at a temperature of -320° Fahrenheit (-196° Celsius), it has made testing of new materials far more practical and widespread.

The benefit of superconducting technology to conventional society still requires materials that can operate at close to room temperature. Since superconductors offer literally no resistance to electrical flow, current could pass through superconducting wire nearly indefinitely. This would reduce power consumption rates for all electrical needs, as well as make such devices ultra-fast compared to standard electronics technology. Powerful magnets would become available for affordable magnetic levitation trains, medical applications, and fusion energy production. As well, such superconductor technologies could include the development of quantum computers potentially hundreds of millions of times faster at processing data than those that exist in 2011.