摘要
本文利用高温固相反应法合成了六角Y1-xHoxMn_(0.8)Fe_(0.2)O_(3)多晶样品,研究Ho^(3+)掺杂对YMn_(0.8)Fe_(0.2)O_(3)微结构以及磁性质的影响。X射线衍射和拉曼测量结果显示所有样品均为单相六角结构,当Ho^(3+)掺杂浓度低于0.15时,晶格常数a、c,晶胞体积及Mn—O键长均随着掺杂浓度的增加而减小。A位稀土原子位移差以及拉曼声子模式的变化表明随着Ho^(3+)掺杂比例增加,A位稀土原子相对于平面的偏移减小,MnO5双锥体倾斜角减小,B位Mn^(3+)的三聚作用被削弱,Mn^(3+)—O2-—Mn^(3+)间超交换作用减弱,反铁磁(AFM)序被抑制,反铁磁转变温度下降。磁性测量显示低温下Y_(0.9)Ho_(0.1)Mn_(0.8)Fe_(0.2)O_(3)的磁化强度显著增强,弱铁磁(WFM)序增加,归因于Ho^(3+)加入后系统磁阻挫行为的降低及Ho^(3+)—O^(2-)—Mn^(3+)间自旋交换作用产生的铁磁序。这为进一步探索室温多铁性材料提供了思路。
Hexagonal Y1-xHoxMn0.8Fe0.2O3polycrystalline samples were synthesized by high-temperature solid-state reaction method.The effects of Ho^(3+)doping on microstructure and magnetic properties of YMn_(0.8)Fe_(0.2)O_(3)were investigated in this paper.X-ray diffraction(XRD)and Raman spectra(RS)show that all samples are of single-phase hexagonal structure without another impurity phase.When the doping concentration(x)of Ho^(3+)is lower than 0.15,the lattice constants,unit cell volume and bond length between the Mn—O of the samples decrease with x increasing.The decrease of the lattice constants may be related to the interaction between the Mn^(3+)/Fe^(3+)3d orbital and the Ho^(3+)4f orbital,resulting in lattice distortion and electron loss.The displacements of the rare-earth atoms at the A-site relative to the plane and the inclination of the MnO_(5)bipyramids are suppressed with increasing doping concentration,which is demonstrated by the shift deviations of the rare-earth atoms and the variations of the Raman phonon modes.At the same time,the trimerization of Mn^(3+)at the B-site is weakened.The magnetic properties of the samples were measured using the superconductor quantum interference device(SQUID).Results show that the antiferromagnetic(AFM)order decreases upon Ho^(3+)doping,consistent with the reduced superexchange interaction between Mn^(3+)—O^(2-)—Mn^(3+).The AFM transition temperature TNdecreases.Besides,the magnetization of the samples and the weak ferromagnetic(WFM)order at low temperature are significantly enhanced,which is attributed to the suppressed magnetic resistance behavior of the system and the ferromagnetic order generated by the spin exchange interaction between Ho^(3+)—O^(2-)—Mn^(3+).These provide an idea for us to further explore room temperature multiferroic materials.
作者
张爱梅
潘茜茜
张大山
朱佳佳
吴小山
ZHANG Aimei;PAN Xixi;ZHANG Dashan;ZHU Jiajia;WU Xiaoshan(College of Science,Hohai University,Nanjing 211100,China;National Laboratory of Solid State Microstructures,Nanjing University,Nanjing 210093,China)
出处
《人工晶体学报》
CAS
北大核心
2022年第12期2096-2103,共8页
Journal of Synthetic Crystals
基金
国家自然科学基金(11404091)
江苏省自然科学基金(BK20140839)。
