Hendrika Johanna van Leeuwen

Hendrika Johanna van Leeuwen (July 3, 1887 – February 26, 1974) was a Dutch theoretical physicist known for her early contributions to the theory of magnetism. She demonstrated that magnetism in matter can only be explained using quantum mechanics. She was one of the first women to study physics at a university level in the Netherlands.

Biography Hendrika Johanna van Leeuwen was born on 3 July 1887 in The Hague, Netherlands, the daughter of Pieter Eliza van Leeuwen and Maria Wilhelmina Schepman. She and her sister enrolled at The Hague Boys' School when it began accepting female students in 1901, although it still required applying for a special ministerial permit. She was also allowed to take the examination in Greek and Latin, a prerequisite for university studies. explained why magnetism in solids is fundamentally a quantum mechanical effect. Her starting point was Lorentz's classical electron theory and his observation that classical free-moving electrons in a metal do not generate a net magnetic moment. She examined a range of other systems and concluded that any classical system in a magnetic field and in thermal equilibrium has no magnetic moment. In other words, classical physics cannot produce any kind of magnetism.

Van Leeuwen continued to investigate magnetic materials at Technische Hogeschool Delft (now Delft University of Technology). In September 1920, she was appointed an assistant, a role she held for nearly 30 years. In this position, she supervised laboratory courses in electrical engineering. Her teaching was appreciated by her students, but it left her with little time for research. alt=A black and white photo of formally dressed men and women who pose for a picture in a sumptuously decorated room. There are three to four rows of indivudals, some sitting and some standing. They are all gathered around Hendrik Lorentz and his wife who are seated at the center front in large throne-like chairs. Van Leeuwen attended the golden anniversary of the doctorate of Hendrik Lorentz. In this photograph of the dinner guests, Van Leeuwen is standing to the left of Albert Einstein, below Niels Bohr. Van Leeuwen remained close with her doctoral advisor Lorentz until his death in 1928.

Selected works