A Second Generation of Curies

When the romantic relationship between Fred and Irène became known, cynics claimed that the gregarious “prince consort” was wooing the awkward “crown princess” of the Radium Institute only to advance his career.

Jean-Frédéric Joliot (1900-1958) and Irène Curie (1897-1956)

MARIE CURIE'S LAST YEARS were brightened by the flourishing collaboration between her two lab assistants, her daughter Irène and young Frédéric Joliot. Just as Marie and Pierre had combined personal love with professional commitment, so did the Joliot-Curies. Irène and Fred shared not only a devotion to scientific research but also similar political outlooks as well as a love of sports.

“The fame and the achievement of her parents neither discouraged nor intimidated her....Her sincere love of science, her gifts, inspired in her only one ambition: to work forever in that laboratory which she had seen go up.” --Eve Curie on her sister Irène

Like Pierre Curie, Fred Joliot lacked impeccable academic credentials. But he had graduated first in his engineering class at the Paris Municipal School of Industrial Physics and Chemistry, where he studied under Paul Langevin, the Curies' colleague and Marie's erstwhile love. In 1925 Langevin helped place Fred at the Radium Institute as a junior assistant to Marie Curie. By that time Irène, two and a half years Fred's senior, had been awarded her doctorate for studies of the alpha rays of polonium (the first of the two elements her mother had discovered 27 years earlier). About a year after Fred's arrival in the lab, the couple married.

“I rediscovered in [Pierre Curie's] daughter the same purity, his good sense, his humility.” --Frédéric Joliot

DOUBTFUL THAT THE MARRIAGE WOULD LAST, Marie Curie not only insisted on a prenuptial agreement but also confirmed that Irène would inherit the use of the radium at the lab. The young couple struggled to make ends meet, with Fred doing some teaching on the side. Despite his many responsibilities, he was able in 1930 to complete his doctorate on properties of compounds of polonium. For a while his financial concerns led him to contemplate leaving research for a better-paying career in industry.

Before 1928, when they began to sign their scientific articles jointly, Irène and Fred had each published some solid work as individuals, but neither had demonstrated outstanding scientific abilities. Together they brushed greatness twice before striking pay dirt. In 1932 they noted the unusual result of an experiment they performed, but failed to understand it completely. That left the discovery of the neutron to James Chadwick. In another experiment, drawing an incorrect conclusion about the mysterious outcome, they ceded the discovery of the positron to C. D. Anderson.

in their basement lab at the Radium Institute led them to a correct and very significant conclusion in mid-January 1934. By bombarding stable elements with nuclear projectiles, they were the first to discover artificial radioactivity--a normal element was changed to a radioactive one through human intervention.

Persistent rumors about the strength of Joliot's attachment to Irène (shown above at a 1929 conference on beta and gamma rays held at the Cavendish Laboratory) led him to announce to an acquaintance, “But I do love my wife. I love her very much.” Marie Curie, shown here with the Joliot-Curies and their young children, soon acknowledged her son-in-law's abilities. The young man, she said, was “a skyrocket.”

“With the neutron we were too late. With the positron we were too late. Now we are in time.”
--Joliot to a student, Jan. 1934

Joliot in 1939 with fellow scientists Lew Kowarski and Hans Halban around a cloud chamber, as they began work on uranium fission. When Joliot told Irène that the cloud chamber was “the most beautiful phenomenon in the world,”
she--by now the mother of two children--corrected him: “Yes, my dear, it would be the most beautiful phenomenon in the world--if it were not for childbirth.”

THANKS TO THEIR DISCOVERY, artificially radioactive atoms could now be prepared relatively inexpensively. The tedious labor and high cost of separating naturally occurring radioactive elements like radium from their ores would no longer impede the progress of nuclear physics and medicine. Their discovery brought the pair the 1935 Nobel Prize for Chemistry.

“The results of your researches are of capital importance for pure science, but in addition, physiologists, doctors, and the whole of suffering humanity hope to gain from your discoveries remedies of inestimable value.”--1935 Nobel Prize for Chemistry to Irène Joliot-Curie and Frédéric Joliot

W ORKING SEPARATELY after receiving the Nobel Prize and the fame and obligations that went with it, Irène and Fred each took on administrative duties and students. Irène accepted the position of Undersecretary for Scientific Research in a Socialist-Communist coalition government, but political maneuvers were not to her taste and she soon returned to the lab. In 1938 her group did painstaking work on uranium with puzzling results, which provoked German scientists to research that led to the discovery of nuclear fission. Fred's group, recognizing a potentially immense source of energy, began pioneering work on chain reactions. When Germany invaded France in 1940, his collaborators fled and helped create the British atomic energy program, leading to the American Manhattan Project. Fred and Irène decided to remain in their homeland.

The End of the Curie Hold on French Science

2000 - American Institute of Physics