Structure and Magnetocaloric Properties in Perovskitelike Lal-xNaxMnOz Powders
CHEN Wei1,3, ZHONG Wei1,2, HOU Deng-lu3, DING Wei-ping2, DU You-wei1, YAN Qi-jie2
1National Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093
2Department of Chemistry, Nanjing University, Nanjing 210093
3Department of Physics, Hebei Normal University, Shijiazhuang 050091
Structure and Magnetocaloric Properties in Perovskitelike Lal-xNaxMnOz Powders
1National Laboratory of Solid State Microstructure, Nanjing University, Nanjing 210093
2Department of Chemistry, Nanjing University, Nanjing 210093
3Department of Physics, Hebei Normal University, Shijiazhuang 050091
Abstract： Perovskitelike manganese oxides Lal-xNaxMnOz (x = 0.075, 0.100, 0.165, 0.200) have been fabricated using sol-gel technique. Structure analysis, temperature programmed reduction (TPR) technique and magnetic measurement have been used to study the effect of Na ion substituted amount on Mn-O distance, the oxygen content, and the magnetocaloric properties of these materials. Results show there is no clear correlation between the substituted amount and mean Mn valence, but a close relationship is observed between Tc and the bond distance of Mn-O. These materials have quite large magnetic entropy changes upon an application of a low magnetic field and can be utilized as more suitable candidates for magnetic refrigerants with wide temperature span.
1998, Vol. 15 
