基于中子衍射的六方相Er1-xYxMnO3结构和磁学性能研究

为研究六方钙钛矿氧化物中磁结构和稀土离子对磁性能的影响，以六方相ErMnO3为母体，通过非磁性Y3+离子对磁性稀土Er3+离子的替代，利用X射线衍射、中子粉末衍射和磁性测量等表征手段，对六方化合物Er1-xYxMnO3的晶体结构和磁性进行系统研究。研究结果表明，Y3+离子的掺杂并未引起晶体结构和磁结构的明显改变，同时发现六方晶体结构随温度的增加呈各向异性热膨胀，在ab面内膨胀而沿着c轴收缩。中子衍射实验结果表明，Er04Y06MnO3样品的有序温度约为79 K，低温下系统的基态为反铁磁性，结构为Γ2（P63c′m′）或Γ4（P63′c′m）组态，与Er08Y02MnO3相同。磁化测试结果表明，非磁性Y3+离子掺杂量的增加削弱了磁化强度，2 K时磁性稀土离子Er3+的自旋有序在外磁场下表现出铁磁信号。该研究阐明了Er1-xYxMnO3的磁性本质和稀土磁性调控特性，为其潜在应用提供了有力指导。

Research on Structure and Magnetism of Hexagonal Er1-xYxMnO3 Based on Neutron Diffraction

The Y-doped hexagonal perovskites ErMnO3 were synthesized and systematically investigated by X ray diffraction, magnetometry and neutron powder diffraction, to elaborate the effect of the magnetic rare earth ions on the magnetic Mn3+ sublattice as well as the magnetization property at low temperature. The results of both X ray and neutron diffraction show that the crystal structure and magnetic structure are almost unaffected by Y3+ doping and maintain the undoped structure, implying a weak interaction between Er3+ and Mn3+. Meanwhile, an anisotropic thermal expansion behavior is disclosed for this hexagonal system, with a dilates while c contracts with the increase of temperature. The neutron diffraction data confirm that the ordering temperature is approximately 79 K for Er04Y06MnO3 sample below which Mn3+ sublattice order adopts a Γ2(P63c′m′) or Γ4(P63′c′m) ground state, identical to Er08Y02MnO3. The magnetometry measurements show that the spin of Er3+ is ordered and coupled with Mn3+ sublattice at low temperature, and the magnetization is weakened by the Y3+ doping. In conclusion, the result provides a deep insight into the magnetism of hexagonal ErMnO3 system, which offers a guidance for the potential application of this intriguing system.