arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1903.08366cond-mat.str-el
收藏

蜂窝材料Ag $_{3}$ LiMn $_{2}$ O $_{6}$的结构、热力学和局域探针研究

Structural, thermodynamic, and local probe investigations of a honeycomb material Ag$_{3}$LiMn$_{2}$O$_{6}$

R. Kumar, Tusharkanti Dey, P. M. Ette, K. Ramesha, A. Chakraborty, I. Dasgupta, R. Eremina, Sándor Tóth, A. Shahee, S. Kundu, M. Prinz-Zwick, A. A. Gippius, H. … 展开作者

R. Kumar, Tusharkanti Dey, P. M. Ette, K. Ramesha, A. Chakraborty, I. Dasgupta, R. Eremina, Sándor Tóth, A. Shahee, S. Kundu, M. Prinz-Zwick, A. A. Gippius, H. A. Krug von Nidda, N. Büttgen, P. Gegenwart, A. V. Mahajan

摘要:

系统Ag [Li $_{1/3}$ Mn $_{2/3}$] O $_{2}$属于四元3R-铜铁矿族,并且以单斜对称性结晶,空间群为$C\,2/m$,并且磁性Mn $^{4+}$($S=3/2$)离子在$ab$-平面中形成蜂窝网络。从我们的磁化率数据推断出在50 K附近的异常和反铁磁(AFM)耦合(居里-外斯温度$θ_{CW}\sim-51$ K)的存在。磁比热在48K附近清楚地表明了磁有序的开始,高于有序温度的磁熵没有达到预期值,表明存在短程磁关联.在接近有序化温度$T_{\rm N}$时的(ESR)谱线增宽可以用$T_{\rm KT}=40(1)$ K的Berezinski-Kosterlitz-less-Berezinski-Kosterlitz(BKT)方案描述。$^{7}$ Li NMR谱线位移探测作为温度的函数跟踪磁耦合Mn $^{4+}$离子的静态磁化率(KPDMATHABMX)。$^{7}$ Li自旋-晶格弛豫速率(1/$T$ $_{1}$)在低于约50 K时呈现急剧下降。结合我们的本体和局部探针测量,我们建立了蜂窝系统Ag $_{3}$ LiMn $_{2}$ O $_{6}$的有序基态的存在。我们的从头计算电子结构计算表明,在$ab$-平面,最近邻(NN)交换相互作用是强和AFM,而下一个NN和第三个NN交换相互作用分别是FM和AFM。在没有任何挫折的情况下,预计该系统将表现出与实验一致的长程AFM有序。

英文摘要:

The system Ag[Li$_{1/3}$Mn$_{2/3}$]O$_{2}$ belongs to a quaternary 3R-delafossite family and crystallizes in a monoclinic symmetry with space group $C\,2/m$ and the magnetic Mn$^{4+}$($S=3/2$) ions form a honeycomb network in the $ab$-plane. An anomaly around 50 K and the presence of antiferromagnetic (AFM) coupling (Curie-Weiss temperature $θ_{CW}\sim-51$ K) were inferred from our magnetic susceptibility data. The magnetic specific heat clearly manifests the onset of magnetic ordering in the vicinity of 48\,K and the recovered magnetic entropy, above the ordering temperature, falls short of the expected value, implying the presence of short-range magnetic correlations. The (ESR) line broadening on approaching the ordering temperature $T_{\rm N}$ could be described in terms of a Berezinski-Kosterlitz-Thouless (BKT) scenario with $T_{\rm KT}=40(1)$ K. $^{7}$Li NMR line-shift probed as a function of temperature tracks the static susceptibility (K$_{iso}$) of magnetically coupled Mn$^{4+}$ ions. The $^{7}$Li spin-lattice relaxation rate (1/$T$$_{1}$) exhibits a sharp decrease below about 50 K. Combining our bulk and local probe measurements, we establish the presence of an ordered ground state for the honeycomb system Ag$_{3}$LiMn$_{2}$O$_{6}$.Our ab-initio electronic structure calculations suggest that in the $ab$-plane, the nearest neighbor (NN) exchange interaction is strong and AFM, while the next NN and the third NN exchange interactions are FM and AFM respectively. In the absence of any frustration the system is expected to exhibit long-range, AFM order, in agreement with experiment.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑