Felix Bloch was born on October 23, 1905, in Zürich, Switzerland. He completed his doctoral dissertation at the University of Leipzig in 1928, developing a quantum theory of solids that provided the basis for understanding electrical conduction. He taught at Leipzig until 1933, when Adolf Hitler's rise to power prompted him to emigrate to the United States. He joined the faculty of Stanford University in 1934 and became a naturalized citizen in 1939.
At Stanford, Bloch proposed a method for splitting a beam of neutrons into two components based on their orientation in a magnetic field. Using this method in 1939, he and physicist Luis Alvarez measured the magnetic moment of the neutron. During World War II he contributed to atomic energy research at Los Alamos and radar countermeasures at Harvard University.
Returning to Stanford in 1945, Bloch developed the principle of nuclear magnetic resonance with physicists W.W. Hansen and M.E. Packard, work that proved instrumental in determining the composition and structure of molecules and has since become one of the most important tools in diagnostic medicine. In 1952 he was awarded the Nobel Prize in Physics for this discovery, shared with E.M. Purcell. He later served as the first director general of CERN from 1954 to 1955.
References
Britannica Editors. "Felix Bloch". Encyclopedia Britannica, 19 Oct. 2025, https://www.britannica.com/biography/Felix-Bloch.