双层钙钛矿锰氧化物(La_(0.9)Eu_(0.1))_(4/3)Sr_(5/3)Mn_2O_7的磁性和磁熵变研究

Magnetic and magnetocaloric properties of bilayered perovskite manganite(La_(0.9)Eu_(0.1))_(4/3)Sr_(5/3)Mn_2O_7

本文采用传统固相反应法制备多晶样品(La_(0.9)Eu_(0.1))_(4/3)Sr_(5/3)Mn_2O_7,并对其磁性和磁卡效应进行研究.研究表明:在低温部分出现反铁磁和铁磁相互竞争,在三维铁磁有序转变温度(T_c^(3D)≈75 K)至二维铁磁转变温度(T_c^(2D)≈227 K)范围内出现铁磁顺磁共存;此外,在T_c^(3D)附近,出现了较大的磁熵变,当外加磁场为1 T时其最大磁熵变值为1.69 J/(kg K),这表明该材料可能适合在液氢温区内作为一种磁制冷材料.

（La0.9Eu0A）4/3Sr5/3Mn2O7 polycrystalline sample was prepared by solid state reaction method. The magnetic and magnetocaloric properties have been studied. The competition between FM and AFM interactions was observed at low temperature range, and the coexistence of FM and PM was found in the temperature range of Tc^3D-Tc^2D for this compound. In addition, the magnetic entropy change under 1 T magnetic field is up to 1.69 J/（kg K）, which suggests that such materials may be applied to magnetic refrigeration in the temperature range of liquid hydrogen.