A study of ultrafast switching in a magnetic material has demonstrated that heat alone is a sufficient stimulus for achieving a reversal of the magnetization. The results, published this week in Nature Communications, are relevant for establishing the fundamental limits on the speed of magnetic recording and information processing. Magnetization reversal is a process that has generally been thought to be driven by a directional stimulus, such as an external magnetic field. Thomas Ostler and colleagues show that heat - which has no associated directionality - can also give rise to a magnetization reversal in an alloy consisting of gadolinium, iron and cobalt. The mechanism, which can be induced by simply applying an ultrafast laser pulse, could lead to higher recording densities and increased data rates in magnetic recording media.