Oxford University physicist Brebis Bleaney died peacefully at his home in Oxford, UK, on 4 November 2006. He is best known for his invention and exploitation of the powerful analytical technique of electron paramagnetic resonance (EPR), alternatively known as electron spin resonance (ESR), which he developed in the years after World War II independently of Evgeny Konstanovich Zavoiskii, who invented the same technique in Russia in 1944.
Born in London on 6 June 1915, Brebis spent most of his life in Oxford, where he became an outstanding figure in Oxford physics. After attending Westminster School, he went to St. John's College, Oxford, in 1934, and graduated with a BA in physics in 1937. He earned a DPhil in physics in 1939; his thesis, “Some Properties of Matter at Very Low Temperatures,” was written under the supervision of Francis Simon.
Brebis's research on low-temperature physics was interrupted by World War II, during which he worked at Oxford for the Admiralty on the development of microwave oscillators for radar. Among his contributions was the design of klystrons at 1.25- and 3-cm wavelengths.
After the war Brebis commenced his exploitation of microwaves in the spectroscopy of gases. Then, stimulated perhaps by the recent invention of the technique of nuclear magnetic resonance in 1945, Brebis invented the analogous technique of EPR, which is a type of microwave spectroscopy of magnetic solids. He became a permanent member of the Oxford physics department as a university lecturer in 1945 and a fellow of St. John's College in 1947.
Brebis's group initially used EPR to study transition ions in solids. The electron resonance measurements were made into a precision spectroscopic tool by reducing linewidth in two ways: dilution to reduce interaction between magnetic ions and cooling to low temperatures to reduce the broadening effects of thermal motion. The work led to a firm understanding of the magnetic and optical properties of transition ions and their interaction with their surroundings and with one another.
By showing what could be achieved with EPR, Brebis's elegant and detailed work stimulated expansion of the technique to study color centers, point defects, and other systems with unpaired electrons in biological, chemical, geological, and physical applications. His interactions with other related research groups, particularly with professional theoreticians Maurice Pryce, Anatole Abragam, Kenneth Stevens, and Roger Elliott, were of enormous mutual benefit and led to the invention of the spin-Hamiltonian, among other things. Brebis dominated the field for a decade, and in recognition of his pioneering work on EPR, he was elected a fellow of the Royal Society in 1950 and awarded the Zavoiskii Prize in 1992.
In 1957 Brebis became Dr Lee's Professor of Experimental Philosophy, a transition that took him from being the leader of the EPR research group to the administrative head of the Clarendon Laboratory, which at that time comprised mostly the Oxford physics department. He presided over a major expansion of the department, which became one of the largest in Europe.
Brebis retired early from his administrative position in 1977 to start a new research group that focused on enhanced nuclear magnetic resonance. He headed the group for about 15 years, as a Warren Fellow of the Royal Society from 1977 to 1980, as a Leverhulme Emeritus Fellow from 1980 to 1982, and finally as an emeritus professor.
With his wife, Betty, who was one of his first graduate students, Brebis wrote his second paper on EPR in 1949. They also wrote the textbook Electricity and Magnetism (Oxford University Press), which was first published in 1957 and is still used today.
I have known Brebis since 1948 when I became one of his undergraduate pupils at St. John's College. I met with him once a week to talk over the week's work. When we had exhausted my problems, he would tell me about the latest piece of his blossoming EPR research. During our meetings he conferred the excitement of research, which influenced me to become one of his graduate students after I received my first degree. Brebis was equally stimulating to his research students; he was in the laboratory every day, often tuning the equipment for better performance. For our first joint publication in 1952, he was at my desk in the lab writing the letter to the editor before I had finished making the measurements.
Brebis was also an extremely caring supervisor. One Saturday, the liquid hydrogen refrigerant in the glass Dewar vessel surrounding the microwave cavity in my EPR spectrometer exploded. Brebis rushed to the lab, then took me to the hospital and waited for hours while I had pieces of glass removed from my leg and minor burns treated. He took me to his house and would not let me go home until he was sure that I could cope on my own.
Brebis was held in great affection by all who knew him, and a meeting held at Oxford to celebrate his 80th birthday attracted a large gathering of friends and former colleagues and students from around the world.
