Marie Curie is one of the most famous names in science. Pierre Curie has somewhat been eclipsed by her fame. His name lives on, though, in one particular physical property, in honor of his research into magnets.
The Curies are the closest anyone can get to science royalty. Not only were they celebrated as such in their own country and abroad, but they started a scientific dynasty that produced three generations of famous scientists, two of which won Nobel Prizes. The dynasty also has a hint of the tragic legend about it. Pierre died at forty-six after being struck by a horse cart. Some say it was the weakness brought due to working with the radioactive material that was going to earn him and his wife worldwide acclaim. The accident happened at the beginning of their scientific fame, and is part of why Pierre is the lesser known of the couple.
Pierre Curie deserves some consideration, though. He did not just search for radioactive elements. He began doing important research in his early twenties. Collaborating with his brother Jacques, the two discovered that crystals can have piezolectric properties - that they generate electric voltage when compressed, and that an electric field can compress them. They used the principles of piezoelectricity to develop sensors that could detect electric currents.
He also discovered an interesting property of magnetic materials. Get a piece of metal and put a magnet next to it, and the metal will make a beeline for the magnet. Heat the metal up, and after a certain temperature (yep — you guessed it — the Curie Point), it will lose its magnetic properties. The atoms are moving around so much that they can't align, and the object drops away from the magnet like it's made of plastic.
Touchingly, it was Marie Sklodowska - Sklodowska was Marie Curie's maiden name - who urged him to write this research up. It earned him his doctorate and an enduring place in history. The point at which magnetic materials loose their magnetic properties is now called The Curie Point.
Top Image: Steve Jurvetson