An innovator in the field of thin films and high-temperature superconductors, Praveen Chaudhari died of cancer on 13 January 2010 at his home in Briarcliff Manor, New York.Praveen was born on 30 November 1937 in Ludhiana, India, and grew up in Calcutta, where he lived through the scarring times of the Indian partition and witnessed the bloodshed of the 1947 riots. Sent to boarding school because he would play truant and go fishing, he eventually received his bachelor’s degree in metallurgy from the Indian Institute of Technology Kharagpur in 1961 and a PhD from MIT in 1966 in physical metallurgy. His thesis, under adviser Michael Bever, was on the irradiation effects on bismuth telluride.Praveen then began his 37-year career at IBM Research in Yorktown Heights, New York. He quickly became the source of inspiration in many areas of thin-film physics, including dislocation interactions and superplasticity, stability of Josephson junctions, and coincidence boundaries between crystals. He was a crucial contributor to IBM’s product development and provided fundamental research in improving reliability for products such as the IBM 370 and 3081 computers. During the early 1970s, he and colleagues Dick Gambino and Jerry Cuomo worked on amorphous gadolinium cobalt films that were successfully integrated into IBM’s magnetic bubble memory devices and adopted later as the basis for read-write media for the magneto-optic disk industry. In recognition of that work, the trio received the 1995 National Medal of Technology.Appointed vice president of science in 1982, Praveen shaped the evolution of IBM’s science research programs in the 1980s. Basic research flourished under his management, and in 1986 and 1987, IBM scientists were awarded the Nobel Prize in Physics for the invention of the scanning tunneling microscope and the discovery of high-temperature superconductivity, respectively.Throughout his professional life, Praveen successfully united careers as an executive and a scientist. During the time that high-T c superconductivity was discovered, Praveen carried out his responsibilities as vice president during the day and then worked in the lab during nights and weekends. Initially, the cuprate superconductors possessed minute critical current densities, and their potential utility was questioned. Guided by his intuitive understanding of materials, Praveen’s team succeeded in growing the first epitaxial yttrium barium copper oxide films with critical current densities two orders of magnitude higher than the earlier results; that increase allayed the utility concerns.Understanding the role of grain boundaries then became important for polycrystalline high-T c superconducting cable applications. Praveen conceived the idea of using bicrystalline substrates, in which crystals of two different orientations share a long, controlled grain boundary; a small group that shared his infectious enthusiasm started using that approach to control-lably study the effects of the films’ grain boundaries. The charismatic IBM vice president did not hesitate to drop by the shielded measurement room at midnight to share cookies and discuss the latest data.The bicrystal research ultimately resulted in the most widely used technology that employs high-T c oxides — Josephson junctions. Bicrystal junctions also provided a foundation for the tricrystal-based experimental confirmation of d-wave pairing in cuprates, which Praveen, remarkably, did not endorse. With the discovery that the critical current decreases with increasing grain boundary angle, bicrystals also became the basis for the development of high-T c coated-conductor technology.In 2003 Praveen retired from IBM and joined Brookhaven National Laboratory as its director. He put BNL on a firm foundation of stability and growth that continues today. His vision led to many successes, including the creation of BNL’s Center for Functional Nanomaterials. In 2006 he stepped down as director and, true to form, returned to the lab; he published a paper on superconducting oxides in Physical Review Letters in 2008. He continued to work part-time at BNL, joined Columbia University as an adjunct professor, and returned to his old laboratory at IBM in Yorktown, where he could often be found running his experiments in the afternoon. He remained active in scientific work up to a few months before his death.Deeply involved in national science policy, Praveen was on the advisory council on superconductivity to Presidents Ronald Reagan and George H. W. Bush and served on the US National Critical Technologies Panel in 1992-93. He advised the government of India and reported on science and technology to two prime ministers, Rajiv Gandhi and P. V. Narasimha Rao.Praveen was a gifted speaker and an excellent motivator who could get others excited about his ideas. He cherished competition, yet he maintained an open door for science discussions and went out of his way to help others with their careers. He switched with ease between hands-on science and demanding management positions, never losing his touch in the lab nor his skills in the conference room. He is greatly missed.Praveen ChaudhariPPT|High resolution© 2010 American Institute of Physics.
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