Pierre Curie (May 15, 1859 - April 19, 1906) ) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity and radioactivity, and Nobel laureate. In 1903 he received the Nobel Prize in Physics with his wife, Marie Salomea Sklodowska-Curie, and Henri Becquerel. He studied ferromagnetism, paramagnetism, and diamagnetism for his doctoral thesis, and discovered the effect of temperature on paramagnetism which is now known as Curie's law. He also discovered that ferromagnetic substances exhibited a critical temperature transition, above which the substances lost their ferromagnetic behavior. This is now known as the Curie point. Pierre worked with his wife Marie in isolating polonium and radium. They were the first to use the term "radioactivity". Pierre and one of his students made the first discovery of nuclear energy, by identifying the continuous emission of heat from radium particles. In 1906, whie crossing the busy Rue Dauphine in the rain he slipped and fell under a heavy horse drawn cart and died instantly. He was 46 years old.