Pierre Curie's squeezed crystals now keep time inside almost every digital circuit
Years before radium made the Curie name famous, Pierre and his older brother Jacques found in 1880 that pressing certain crystals produces a voltage. A year later they showed the reverse: electricity makes crystals flex. That piezoelectric effect now ticks inside the crystal oscillators that nearly all digital circuits depend on.
Curie was born in Paris on 15 May 1859, son of a family doctor, and was taught at home before entering the university's science faculty. Through his grandmother he descended from the Basel mathematician Jean Bernoulli. He joined the Paris school of industrial physics and chemistry, ESPCI, in 1882, and to measure the tiny charges from crystals he and Jacques built a sensitive quartz electrometer that would later serve Marie's research.
His doctorate of 1895 was on magnetism, measured with a torsion balance of his own design. He found that paramagnetism weakens as temperature rises, now Curie's law, and that ferromagnets lose their magnetism above a critical point, the Curie temperature. He also stated a symmetry rule: an effect cannot be more lopsided than whatever causes it, so sand sorting itself by density simply mirrors the direction of gravity.
A physicist friend introduced him to Maria Skłodowska, who joined his lab. She turned down his first proposal and married him in July 1895. Together they isolated polonium and radium, announced in December 1898, and coined the word radioactivity. With his student Albert Laborde, Pierre found that radium gives off heat continuously, and with magnets he sorted its emissions into positive, negative and neutral types. When the Royal Society invited them to London in 1903, Marie was barred from giving the talk, so Lord Kelvin sat beside Marie while Pierre spoke. That year the couple shared the Nobel Prize in Physics with Henri Becquerel, the first married pair so honoured.
Curie, an atheist, also sat in on séances around 1905 as experiments, taking careful notes. On 19 April 1906, crossing the Rue Dauphine in the rain, he slipped under a horse-drawn cart and was killed. Their notebooks, even Marie's cookbooks, are still radioactive and stored in lead boxes. In 1995 the couple were reburied in the Panthéon.
Source: Pierre Curie
