论文标题
F-D交换相互作用和近代散射在ND掺杂的pyrochlore Iridate(EU1-XNDX)2IIR2O7中的作用
Role of f-d exchange interaction and Kondo scattering in Nd doped pyrochlore Iridate (Eu1-xNdx)2Ir2O7
论文作者
论文摘要
我们报告了Pyrochlore Iridate(EU1-XNDX)2IIR2O7的磁化,电阻率,磁倍率和比热的特异性,其中X = 0.0、0.5和1.0,其中旋转轨道耦合,电子相关,磁性挫败感和近距离散射均具有旋转轨道耦合,电子相关性。金属绝缘子过渡温度(T_MI)随着ND含量的增加而降低,但始终与磁不可逆温度(场诱导力矩)一致。低于T_MI的电阻率与激活的(GAP)或任何功率定律(无间隙)依赖性不符合。 Curie常数显示出令人惊讶的结果,ND在IR Sublattice中诱导了单线相关性(降低了Parammoment)。在低温低于10 K的低温下,磁倍率为负,并且随着X的增加而大大增加,并且随着场切换到50 KOE以上的线性依赖性而倍增。低温比热的热量显示了肖特基峰,来自ND矩,表明由F-D交换相互作用引起的Doublet End-End-Enerm水平分裂的存在。所有材料均显示在绝缘区域中存在线性特异性热。 X = 0.0的线性特异性热量的系数不会随外部磁场而变化,但对于X = 1.0材料的超线性变化。我们认为线性比热可能排除了弱相关的阶段,例如魏尔费米子。我们建议,随着在欧盟站点引入ND,系统从手性旋转液体和无间隔的Spinon激发型中进化,并且具有很小的电荷差距到昆多类型的相互作用,可与手性旋转液体相互作用,并在远距离的抗fiferromagnetic下方共存。随着ND浓度的增加,磁化率的巨大增加表明,通过稀土力矩,近代散射在手性旋转液体材料中的重要性。
We report study of magnetization, resistivity, magnetoresistance and specific heat of the pyrochlore Iridate (Eu1-xNdx)2Ir2O7 with x=0.0, 0.5 and 1.0, where spin orbit coupling, electronic correlation, magnetic frustration and Kondo scattering coexists. Metal insulator transition temperature (T_MI) decrease with increase in Nd content but always coincides with magnetic irreversibility temperature (field induced moment). Resistivity below T_MI do not fit with either activated (gap) or to any power law (gapless) dependence. The Curie constant show surprising result, that Nd induces singlet correlation (reduction of para-moment) in Ir sublattice. Magnetoresistance is negative at low temperatures below 10 K and increases strongly with increase in x and vary quadratically with field switching over to linear dependence above 50 kOe. Low temperature specific heat shows Schottky peak, coming from Nd moments, showing existence of doublet split in Nd energy level, arising from f-d exchange interaction. All materials show presence of a linear specific heat in the insulating region. The coefficient of linear specific heat for x= 0.0 does not vary with external magnetic field but varies superlinearly for x = 1.0 materials. We argue that linear specific heat probably rules out weakly correlated phases like Weyl fermions. We propose that with the introduction of Nd at Eu site the system evolves from chiral spin liquid with gapless spinon excitations with a very small charge gap to Kondo type interaction superposed on chiral spin liquid coexisting with long range antiferromagnetic ordering. Huge increase of magnetoresistance with increase in Nd concentrations shows importance of Kondo scattering in the chiral spin liquid material by rare earth moments.