Grain growth and superconductivity of rhenium electrodeposited from water-in-salt electrolytes
Grain growth and superconductivity of rhenium electrodeposited from water-in-salt electrolytes
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DOI：
10.1063/1.5139909
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发表时间：
2020-02-24
影响因子：
3.2
通讯作者：
Huang, Qiang
中科院分区：
文献类型：
--
作者：
Sides, William D.;Hassani, Ehsan;Huang, Qiang
研究电沉积铼 (Re) 薄膜中超导性与薄膜制备条件（即厚度和退火工艺）之间的关系，以了解晶粒尺寸和杂质对薄膜超导转变温度 T-c 的影响。使用盐包水电解质通过减少铼沉积的阴极处的析氢来减轻脆化。沉积态薄膜在 T-c>5.8K 温度下表现出高度无序的原子结构和超导性，与非晶薄膜的预期一致。发现超导临界温度的降低伴随着晶粒生长。然而，对于小于 300nm 的薄膜厚度，晶粒生长受到抑制。这导致在对这些薄膜进行退火时保持临界温度。研究发现，Re 薄膜中的杂质会随着退火而减少，并且在惰性气氛中 220 摄氏度的温度下，晶粒会快速生长。在退火环境中引入氢气进一步促进了晶粒生长。
The relationship between superconductivity and the film preparation conditions, i.e., the thickness and annealing process, in electrodeposited rhenium (Re) films is studied in order to understand the effect of grain size and impurities on the film's superconducting transition temperature, T-c. A water-in-salt electrolyte was used to mitigate embrittlement by reducing hydrogen evolution at the cathode where Re is deposited. The as-deposited films exhibit a highly disordered atomic structure and superconductivity up to a temperature of T-c>5.8K, consistent with that expected from amorphous films. A reduction of the critical temperature of superconductivity is found to accompany grain growth. However, for film thicknesses less than 300nm the grain growth is inhibited. This leads to a retention of the critical temperature upon annealing these thin films. A reduction of impurities in Re films is found to accompany annealing, and significant grain growth is found to proceed rapidly at temperatures of 220 degrees C in inert atmospheres. The introduction of hydrogen in the annealing ambient further facilitates this grain growth.