Kurt Alfred Georg Mendelssohn (7.01.1906—18.09.1980) was an English physicist and a Fellow of the Royal Society (1951). He was born in Berlin. He graduated from the University of Berlin (1930). In 1929—31 he worked at the University of Berlin, in 1931-33 at the university in Breslau, and in 1933-73 at the Clarendon Laboratory of the University of Oxford.
His research was in the field of low-temperature physics, superconductivity and superfluidity. He proposed (1934) using the adiabatic magnetisation of a superconductor for cooling, and also developed a method of cooling by desorption. He studied the properties of liquid helium. Together with J. Daunt he discovered (1939) the mechanocaloric effect in helium, measured the thickness of the surface film of liquid helium (50 — 100 atomic layers), studied its thermal conductivity and established (1938) that in the presence of a temperature gradient liquid helium is transferred from a colder place to a warmer one (the discovery of film transfer). He showed (in the 1950s) that the entropy of the superfluid component of the helium film is zero. He studied (in the 1930s) the superconductivity of alloys. He developed an effective method of determining lattice defects in solids. He postulated the existence of an energy gap for the excited states that contribute to the electronic heat capacity.
The D. Hughes Medal (1967) and the F. Simon Prize (1968). Founder of the journal “Cryogenics” (1966).