Obituary of James S Kouvel

James S Kouvel was born on May 23, 1926, in Jersey City, New Jersey. Combining his studies with service in the US Naval Reserve in the South Pacific from 1944 to 1946, he earned a bachelor’s degree in engineering and a PhD, both from Yale University, in 1946 and 1951 respectively. He was a research fellow at the University of Leeds in England from 1951 to 1953 where he met his future wife, Audrey Lumsden. Returning to the United States, James and Audrey taught and studied respectively at Harvard (1952- 1956). From 1956 to 1969 James was with the General Electric Research Laboratory in Schenectady, NY. Over the years he spent periods as Visiting Professor at the Universities of Paris and Amsterdam and the Atomic Energy Research Establishment at Harwell, England. He also was a consultant at Argonne National Laboratory (1969-1989).

He was a physicist for General Electric Company’s Research and Development Center from 1955 to 1969 before he joined the physics faculty at the University of Illinois at Chicago. A respected national figure in the study of magnetism, Kouvel won the Guggenheim Fellowship (1967-68), was elected to a fellowship of the American Physical Society in 1962 and to a fellowship of the American Association for the Advancement of Science in 1983. He was a member of the editorial advisory board of the Journal of Magnetism and Magnetic Materials since 1975. He was involved in committees with the National Science Foundation and National Research Council. His more than 154 publications received above 3600 quotations.

Joining the Department of Physics at University of Illinois at Chicago in 1969, he established a sustained and distinguished record of research. Kouvel was one of the first persons to identify exchange anisotropy as being responsible for the very interesting properties of certain transition-metal alloys and compounds. Today, these properties are used extensively in the magnetic recording industry. More significantly, later work on this topic by Gruen and Fert was instrumental for them to receive this year’s Nobel Prize. Another milestone in his career was the discovery of giant magnetic moments in NiCu alloys. Until the time of this discovery the magnetic properties of alloys were understood in terms of the rigid band model, which predicted a spatially uniform magnetization density. Kouvel and his co-workers showed that this is not at all the case. Their neutron scattering results demonstrated that the magnetization density is very non-uniform and concentrated in so-called magnetic clusters or giant magnetic moments. This discovery started a flurry of activities involving many scientists world-wide, and eventually led to a complete change in our understanding of magnetic properties of Alloys. Kouvel also contributed extensively in our understanding of magnetic phase transitions. Together with M. Fisher he developed a novel way of analyzing the critical behavior near a ferromagnetic phase transition. This led to a better understanding of the scaling behavior of the magnetization near the transition. These new presentations are referred to in the literature as Arrot-Kouvel plots. His seminal 1964 paper with M. Fisher, which helped to establish an influential method of analysis of critical phenomena, received more then 400 citations.

Later in his career, Kouvel did significant work on a new class of materials, called Spin Glasses. With his students, he helped to elucidate the complex nature of the magnetic interactions in these materials. He developed a new experimental technique to investigate the anisotropy of the magnetic interaction by rotating the sample in a magnetic field and simultaneously measuring two components of the magnetization vector.

Kouvel’s most recent research was on vortex pinning in superconductors. The classic property of a superconductor below its critical temperature namely, its zero resistance to electric current is operational only if the magnetic filaments (known as vortices) produced by the current are prevented from moving. Hence, the strength with which the vortices are pinned inside the material is an important practical problem. Kouvel’s work led to new insight into the pinning mechanism based unconventional magnetic measurements on superconducting samples as they were rotated slowly in fixed magnetic fields. These rotational experiments have been carried out on the new high-Tc superconducting compounds and uncovered many unusual features of their vortex states.