Superconductivity Superconductivity Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials, called superconductors, when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 8, 1911, in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor during its transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood simply as the idealization of
Johannes Bosscha Kamerlingh Onnes was his assistant from 1878 to 1882, after which Kamerlingh Onnes became professor at Leiden University. In 1885 Boscha needed to resign as director because of poor health. His "Verspreide Geschriften" (Diverse Writings) were published in three volumes (Leyden, 1902). In 1855 he married Paulina Emilia Kerkhoven in the town of Voorst. They had four daughters and two sons. The Bosscha Observatory on Java has been named after his son Karel Albert Rudolf Bosscha (1865–1928), who contributed much to the technical development of Indonesia. Johannes Bosscha Johannes Bosscha Jr. (18 November 1831 – 15 April 1911) was a