Felix Bloch
1905–1983, Zürich, Switzerland, Zürich, Switzerland
Swiss-American physicist, a founder of the quantum theory of solids and co-discoverer of nuclear magnetic resonance.
Bloch studied at ETH Zürich and Leipzig, receiving his doctorate in 1928 under Werner Heisenberg with a thesis that founded the Bloch-wave theory of electrons in crystals. After leaving Europe because of Nazism, he settled at Stanford in 1934, becoming the university's first professor to work across fields from neutrons to nuclear magnetism. In 1946 he and his group developed the nuclear induction method detecting nuclear magnetic resonance in bulk matter. He was also the first Director-General of CERN (1954–1955).
Nobel-winning work
At Stanford, Bloch, with William Hansen and Martin Packard, developed the 'nuclear induction' method: a water sample in a strong magnetic field was excited by an orthogonal radio-frequency field, and the signal induced in a second receiver coil revealed the resonance of the nuclear magnetic dipoles. The technique — independent of Edward Purcell's absorption method at Harvard — allowed precise measurement of nuclear magnetic moments and their chemical environments.
NMR became an exquisitely sensitive probe of matter and of chemical structure — the basis of NMR spectroscopy and later magnetic resonance imaging. Bloch also formulated the phenomenological Bloch equations describing spin dynamics; he shared the 1952 Nobel Prize in Physics with Purcell 'for their development of new methods for nuclear magnetic precision measurements and discoveries in connection therewith'.
Workplaces: Stanford University, ETH Zürich
United States, Switzerland