Pierre Curie
Pierre Curie is not as well known as Marie Curie, although Pierre and his brother had done a lot of work before Pierre's marriage and work with Marie. They were the first to use the term 'radioactivity', and were pioneers in its study. Pierre and his brother, Jacques Curie, built a special meter for measuring small amounts of electricity, piezoelectricity and ferromagnetism which Pierre and Marie used in their other discoveries.