Thermal Expansion of Alkaline-Doped Lanthanum Ferrite Near the Neel Temperature

摘要

The thermal expansion and magnetic behaviors of divalent, alkaline-doped lanthanum ferrites (La_(0.9)M_(0.1)FeO_3, M＝Ca, Sr, Ba) were assessed using a combination of dilatometry, magnetometry, time-of-flight neutron diffraction, and high-temperature X-ray diffraction. Neel temperatures were determined through vibrating sample magnetometry and correlated well with changes in thermal expansion behavior observed during both dilatometry and X-ray diffraction. The Neel temperatures observed for pure, Ca-doped, Sr-doped, and Ba-doped lanthanum ferrites were 471℃, 351℃, 465℃, and 466℃, respectively. The effect of divalent substitutions on the magnetic behavior are attributed to charge compensation mechanisms and structural changes in the material.