Size-Induced Effects on the Superconducting Properties of Mo2C Nanoparticles

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• 作者：Manoj K. Kolel-Veetil ; Syed B. Qadri ; Michael Osofsky ; Teddy M. Keller ; Ramasis Goswami ; Stuart A. Wolf
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：November 15, 2007
• 年：2007
• 卷：111
• 期：45
• 页码：16878 - 16882
• 全文大小：569K
• 年卷期：v.111,no.45(November 15, 2007)
• ISSN：1932-7455

文摘

Nanoparticles of molybdenum carbide in two different phases were synthesized by the pyrolysis of a Mo-derived inorganic-organic hybrid system. The size and structure of the Mo₂C nanoparticles were found to beuniquely influenced by the pyrolytic conditions: 2-4 nm particles were produced in the -Mo₂C phase at850 C, and larger particles with diameters ~50-150 nm were formed in the -Mo₂C phase at temperaturesabove 850 C, with a minor amount of the -Mo₂C phase being formed at this temperature. Resistivitymeasurements indicated that the samples containing the 50-150 nm particles were metallic with T_c's above4 K and the sample containing the 2-4 nm particles, including a minor contaminant fraction of the 50-150nm particles, was insulating in behavior. During magnetic measurements, the samples with 50-150 nm particlesappeared to be strongly diamagnetic and the sample with a majority of 2-4 nm particles was observed to beweakly diamagnetic.