Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(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 h...Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(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.展开更多
基金Supported by the National Natural Science Foundation of China under Grate No.59676021 and 85-06 Nano-materials Science。
文摘Perovskitelike manganese oxides La_(l-x)Na_(x)MnO_(z)(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.
