Obituary of Frederic Holtzberg (1922-2012)

Frederic Holtzberg passed away on April 24^th, 2012 after an extended illness. He was 90 years old and lived, with his wife Sylvia, in Greenport, Long Island, NY. He was a distinguished member of the IBM Research Division where he worked from 1952 intermittently through 1993. Holtzberg was a Materials Scientist, trained in Chemistry, but his interests were broad and included other disciplines, in particular Physics, where he made outstanding contributions to our understanding of rare earth materials, especially magnetic semiconductors. He was the co-recipient (with Francis DiSalvo) in 1991 of the APS International Prize for New Materials, now the James C. McGroddy Prize for New Materials , for his discovery of new materials characterized by strong electron correlations. Holtzberg was also a highly valued member of the management team of the Physical Sciences division of the T.J. Watson Research Center from 1963 until 1982. In addition he served the Presidential Office of Science and Technology as trusted advisor on scientific issues from 1959 to 1960.

Born in New York City in 1922, and after service in the U.S. Army during which he was stationed for a time in India, Holtzberg completed his B.S. in Chemistry at Brooklyn College in 1947. His Ph.D. on the structure of Formic Acid was completed in 1952 at the Polytechnic Institute of Brooklyn under the guidance of the famous crystallographer, I. Fankuchen. That year he joined the Watson Research center of the IBM Corporation, housed at that time on a site at Columbia University. His employment there was interrupted when he took a leave of absence to become Technical Assistant and consultant to the Office of Science and Technology at the White House from 1959 to 1960. He then rejoined the Watson Research Center, now at its new site in Westchester County, NY.

Dr. Holtzberg’s career as a materials scientist spanned many of the important developments in rare earth research. His talents as a solid state chemist to perform new syntheses and to fabricate novel materials as well as his insight, which led to the exploration of new physical phenomena in many of these systems, reflected his strong interdisciplinary abilities. In fact, his contributions to the synthesis of new rare earth compounds and alloys as well as the study of their physical properties were critical in developing the fields of magnetic semiconductor, intermediate valence and, lastly, the high temperature superconductors.

In the following we outline two aspects of Dr. Holtzberg’s activities that have had critical impact on materials research. The first is that his creation of new rare earth materials initiated several fields of research which are still actively pursued. The other has to do with his wide family of collaborators. These include solid state physicists and chemists from Great Britain, Germany, and France, not to speak of his American colleagues. Thus, Holtzberg not only created the samples without which the experiments were not possible, but he also initiated ideas and directions for such experiments.

Dr. Holtzberg had been at IBM for approximately nine years when he, with S. Methfessel, embarked on original studies on the Eu-chalogenides and their alloys. Interest in these materials stemmed from the work of Matthias, et al. (1961), who discovered EuO to be a ferromagnetic insulator. It was Holtzberg’s and Methfessel’s idea to produce magnetic semiconductors of this class of materials. This led to their well-known work during the years 1964 through 1966 in which they established the magnetic phase diagrams of the solid solution systems Eu_1-xR_xX, with X = S, Se, Te and the R = Gd, La, Lu, Th, Dy, and Y. The importance of these studies cannot be overemphasized, since at that time all interest in the Eu compounds focused on the pure materials. Dr. Holtzberg’s work in proving that the entire series of solid solutions could be produced in single crystal form, that with addition of the trivalent rare earth atoms the materials became good conductors and that these electrons modified the magnetic exchange influenced all rare earth research thereafter. It led swiftly to major programs in the alloy systems at the ETH, MIT and IBM.

His expertise in the synthesis of rare earth compounds and alloys led Holtzberg naturally to the subject of intermediate valence. In 1970, Jayaraman at Bell Laboratories had discovered the pressure induced metal-insulator (black to gold) transition in SmS in which the lattice constant collapsed by 5% without a change in crystal structure. Holtzberg discovered in 1973 that the transition could be induced by ‘chemical pressure’ by making solid solutions of SmS with LaS and YS. Independently Jayaraman reported on a similar study using GdS the same year.

In 1975, Dr. Holtzberg visited the CRTRT at Grenoble for a year and started a very effective program on rare earth research. It should be noted that until that time the work at CRTBT had involved principally transition metal alloys. Holtzberg’s presence changed the emphasis of materials research at the laboratory. His effectiveness as a collaborator and leader may best he summarized by noting that of his last one hundred and fifty publications, only one third involved colleagues solely from IBM. All others included his many international collaborators. Materials prepared and studied include magnetic semiconductors, intermediate valence compounds, spin glasses, some of the first single crystals of reentrant superconductors such as the Chevrel phases, Mn doped II-VI semiconductors and the high temperature yttrium based superconductors. Holtzberg’s contribution to the latter is of particular importance, since he developed the first technique for the growth of free standing crystals of these materials. In order to begin to understand the mechanism for superconductivity, it had become evident that free standing single crystals were necessary to perform experiments such as transport, magnetization, infra-red absorption and tunneling spectroscopy.

Dr. Holtzberg will be remembered by his many colleagues for his wisdom and great sense of humor. In his years at IBM he selflessly taught and mentored two generations of younger scientists including the three authors of this obituary. Fred attacked each materials problem with dedication, humility and extraordinary skill. It is a testament to his innate modesty that he was not a coauthor of many of the first detailed studies on rare earth alloy systems, since the samples had not been specifically made for the reported experiments. As one of the pioneers of multidisciplinary materials research, his achievements remain a model for excellent science in a truly interactive mode with chemists, ceramicists and physicists.