Former Director, Tohoku Institute of Technology and Professor Emeritus, Tohoku University.
From the beginning of his engineering career in 1949 at Tokyo Tsushin Kogyo Ltd., later known as Sony, Iwasaki specialized in the technology of magnetic recording. He expanded on this interest after becoming a professor at Tohoku University, and throughout the next two decades made significant contributions including the development of metal-based tapes and high-density recording technologies. It was in the mid-1970s that he devised what would become his signature idea. Since the beginnings of magnetic recording, the magnetized grains on a tape or other medium were longitudinally, or horizontally, oriented. On tape, for instance, this means that each grain was situated parallel to the tape's length, a system known as longitudinal magnetic recording (LMR). Thus, the capacity of a given length of tape was determined by how many grains could fit within that two-dimensional area. Iwasaki's inspiration opened up the third dimension. He realized that if a magnetic medium could be magnetized perpendicular to its surface, more magnetic grains would fit within a given area, vastly increasing storage capacity. Such a technique also allows the use of recording media with higher magnetic coercivity that are less susceptible to magnetic degradation and loss of signal over time. Iwasaki had invented perpendicular magnetic recording (PMR). Despite the elegant beauty of Iwasaki's conception and a great deal of initial enthusiasm for its potential, ensuing leaps forward in LMR technologies pushed PMR to the background for a time, a period Iwasaki refers to as the technology's "Death Valley." Iwasaki kept the PMR fires burning by continuing to write papers and hold conferences on his ideas. Some three decades after he first announced the concept, PMR came of age—largely due to the efforts of Mark Kryder.