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arXiv 1702.01138cond-mat.str-elcond-mat.mtrl-sci
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Li(Mn,Fe)PO $_4$单晶的高压光学浮区法生长

High-pressure optical floating-zone growth of Li(Mn,Fe)PO$_4$ single crystals

Christoph Neef, Hubert Wadepohl, Hans-Peter Meyer, Rüdiger Klingeler

摘要:

采用移动浮区法在30 bar的氩气压力下生长了含$0\leq x \leq 1$的LiMn $_{1-x}$ Fe $_x$ PO $_4$单晶。对于不同的掺杂水平,生长过程进行了优化的组合物依赖的有效的光吸收和材料的透明度。一个凸形的晶体/熔体界面,由入射光的角度确定,被确定为是一个成功的生长特别重要。所得到的大的单晶颗粒是化学计量的。结构精修表明,晶格参数以及原子位置和键长线性依赖于Mn:Fe比。定向立方样品与几毫米$^3$的体积用于磁性研究,这意味着所有组合物的反铁磁基态。Néel温度从LiMnPO $_4$中的$T_N$ = 32.5(5)K变化到LiFePO $_4$中的49.5(5)K,而有序相中的易磁化轴在$x<0.2$掺杂Fe后从结晶学$a$ -翻转到$b$ -轴。

英文摘要:

Mm-sized LiMn$_{1-x}$Fe$_x$PO$_4$ single crystals with $0\leq x \leq 1$ were grown by means of the traveling floating-zone technique at elevated Argon pressure of 30~bar. For the various doping levels, the growth process was optimized with respect to the composition-dependant effective light absorption and transparency of the materials. A convex crystal/melt interface, determined by the angle of incident light, was identified to be particularly crucial for a successful growth. The resulting large single crystalline grains are stoichiometric. Structure refinement shows that lattice parameters as well as the atomic positions and bond lengths linearly depend on the Mn:Fe-ratio. Oriented cuboidal samples with several mm$^3$ of volume were used for magnetic studies which imply an antiferromagnetic ground state for all compositions. The Néel-temperature changes from $T_N$ = 32.5(5) K in LiMnPO$_4$ to 49.5(5) K in LiFePO$_4$ while the easy magnetic axis in the ordered phase flips from the crystallographic $a$- to the $b$-axis upon Fe-doping of $x<0.2$.

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。

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