 Criterion for Ferromagnetism from Observations of Magnetic Isotherms by Anthony Arrott

Physical Review 108, 1394 (1957), published 15 December 1957.

Primary publisher abstract: within a molecular-field description, the onset criterion follows from magnetisation cubed being proportional to internal field at the Curie point. This source supports the named plotting method, not the numerical estimates independently read from an exam graph.