Scientists from the Bell Laboratories in the USA have made high temperature superconductors using the ball-shaped carbon molecules known as Buckminsterfullerine, after the American architect Buckminster Fuller. The new compounds became superconducting at below -138°C, above the temperature of liquid nitrogen used to cool superconducting materials.

The research, published in the journal Science, was carried out by a team led by Hendrik Schon. He and his team succeeded in inserting molecules of chloroform and bromoform inside the carbon skeletons of the spherical carbon molecules, generally known familiarly as Bucky balls. They then found they could manipulate the properties of the resulting material using an electric field to change it from an insulator to a superconductor.

These carbon-based superconducting materials are potentially cheaper than copper oxide-based superconductors that are already being exploited commercially in superconducting magnets and superconducting cables. The key, however, is to push up the temperature at which they switch from being insulators to becoming superconductors.

The effect of the inserted chloroform and bromoform into the Bucky ball carbon crystal structure is to force the spherical molecules of carbon farther apart, increasing the amount of electric charge the material can contain. Whether this can eventually lead to a superconducting material that does not need any cooling depends upon how far the molecules can be forced apart before the crystal structure collapses. However it does represent an attractive avenue of research towards the goal of a room-temperature superconducting material.