Scientists of the Department of Physics at the University of Hamburg, Germany, detected the magnetic states of atoms on a surface using only heat. The respective study is published in a recent volume of Science. A magnetic needle heated by a laser beam was placed in close proximity to a magnetic surface with a gap of only a few atoms width. The temperature difference between the needle and the surface generates an electric voltage. Scanning the needle across the surface, the scientists showed that this thermovoltage depends on the magnetic orientation of the individual atom below the needle.