The Physical Property Of Superconductor LaAg1−cMnc(c=0.1~0.7)
碩士 === 國立中興大學 === 物理學系所 === 105 === The binary compound of LaAg in this study has superconducting critical temperature 0.9 K. A serious of LaAg1-cMnc (c = 0.1 ~ 0.7) compounds were made by arc-melt argon welding method. The quality of the specimen is characterized by X-Ray powder diffractometer (XRD...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2017
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| Online Access: | http://ndltd.ncl.edu.tw/handle/41268596748560581184 |
| Summary: | 碩士 === 國立中興大學 === 物理學系所 === 105 === The binary compound of LaAg in this study has superconducting critical temperature 0.9 K. A serious of LaAg1-cMnc (c = 0.1 ~ 0.7) compounds were made by arc-melt argon welding method. The quality of the specimen is characterized by X-Ray powder diffractometer (XRD). The superconducting behavior and magnetic hysteresis were measured by Superconducting Quantum Interference Device (SQUID) over wide temperature region of 2 K to 300 K under various applied magnetic fields. It is found that the superconducting critical temperature has extremely fascinating change.
There is a relatively high superconducting critical temperature Tc = 5.7 K for the c = 0.1 specimen, and the hysteresis curve shows a superconducting loop with a paramagnetic background.
There are rare-earth element La and transition-metal element Mn in the three dimensional LaAg1−cMnc system, both of them own the magnetic moment. According to the BCS theory, the superconductivity cannot occur under this magnetic background. For such an unconventional superconductor it is worthy to discuss the formation mechanism of superconducting pairs. An antiferromagnetic-spin-fluctuation model was proposed to be the formation mechanism of Cooper electronic pairs in these LaAg1-cMnc compounds
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