Studies of the ionic ferromagnet (LaPb)MnO₃ II. Static magnetization properties from 0 to 800 °K

Abstract

The static magnetization of the family of compounds La 1−x Pb x MnO 3 (0.25 < x < 0.45) has been measured from close to absolute zero to about 800 °K. The compounds are ferromagnetic, with Curie temperatures ranging from 315 to 350 °K. At absolute zero, the magnetization agrees to within 3% of that expected from the average spin per formula unit. The spontaneous magnetization decreases more rapidly than predicted by the Brillouin function for a normal ferromagnet for 0.9 < T/T c < 1. Just above the Curie temperature, the reciprocal susceptibility versus temperature curve exhibits a slight curvature; at higher temperatures the susceptibility follows the Curie–Weiss Law. The average spin obtained from the Curie constant agrees well with that obtained from the chemical formula. It is concluded that the ferromagnetism has its origin primarily in the itinerant d electrons that lie in a narrow double-exchange band, although lattice distortion may also have an influence.