The thermal expansion coefficient of Nd-Fe-B and Sm-Co permanent magnets in the region of the Curie point.

A dilatometric study results on the linear thermal expansion coefficient (LTEC) of Nd-Fe-B and Sm-Co permanent magnets are presented. The experimental data in the temperature range 200–750 K and 293–1163 K, respectively, are obtained. The measurements were made with an error 3%. The character of the change of the linear thermal expansion coefficient in the vicinity of the Curie point is established. The critical exponents of the LTEC for magnetic phase transitions are defined. [ABSTRACT FROM AUTHOR]