Stefan Procopiu was born in Bârlad, on 19 January 1890. Procopiu dedicated himself to science and research from the time he was still a student. The first remarkable results of his research were published in 1913, in Bulletin scientifique de l’Académie roumaine de sciences, within the famous paper Determining the Molecular Magnetic Moment by M. Planck’s Quantum Theory. After studying Planck’s quantum theory and Langevin’s magnetism theory, Procopiu was the first to establish in the whole world the value of the molecular magnetic moment also named the theoretic magneton, M. It is recognized that Stefan Procopiu calculated the value of the theoretic magneton two years before Prof. A. Bohr of Denmark. In the Romanian specialized literature, this discovery is known as the Bohr-Procopiu magneton. Procopiu published 1913 the paper Experimental Research on Wireless Telegraphy, while in 1916 he invented a device for locating and establishing the depth of bullets in the bodies of the wounded. From1919 in Paris, he attended the courses of famous scientists of the epoch, such as Gabriel Lippman, Marie Curie, Paul Langevin, Aymé Cotton. In 1921, Procopiu discovered and analyzed in the Physics Laboratory of Sorbonne University a new optical phenomenon which consisted in the longitudinal depolarization of light by suspensions and colloids. In 1930, the above phenomenon was designated as Procopiu Phenomenon by prof. A. Boutaric. On 5 March 1924, Procopiu obtained the title of doctor in physics with the work On The Electric Brefringence of Suspensions, sustained in frnt of a commission including coordinator prof. Aymé Cotton, and cross-examiners Charles Fabry and H. Mouton. Another important discovery, resulting from prof. Procopiu’s research, is the electromotive force of galvanic elements. In the field of ferromagnetism, he undertook numerous studies whose results were published in many specialized magazines in Romania and abroad. Thus, in 1930, studying the Barkhausen effect, which consists in transferring alternative current through wires of ferromagnetic material, he discovered a circular effect of magnetic discontinuity. In 1951, this effect was named Procopiu Effect. A significant technical application of this effect was achieved by the American physicist Roman Storski in creating calculation devices. Back in Romania in 1925, with an unquestionable scientific renown in the field of physics, on 15 January Procopiu was appointed a professor in ordinary of the Gravitation, Heat and Electricity Department of “Al. I. Cuza” University of Iasi, department which he coordinated until 1962, the year of his retirement.