| Summary: | 碩士 === 國立中央大學 === 物理研究所 === 99 === The copper nanoparticles were manufactured by the thermal evaporation method. We got the sample of cuprous oxide from a process that heated the copper in a condition in which not enough oxygen, and got the sample of cupric oxide from the process that heated in air. The chemical composition of the sample were pure Cu2O and CuO by X-ray diffraction and General Structure Analysis System. The mean particle diameter of Cu2O and CuO nanoparticles were 5.5 nm and 3.6 nm that determined respectively by X-ray diffraction patterns.
Magnetic properties of nanoparticles were measured by Physical Property Measurement System. The M(H) of Cu2O in various temperature were observed, then fitted the M(H) curve by a Langevin function, a Brillouin function and a diamagnetic term. From a result of fitting curve at all temperature, there were three effect in the system, spin polarization, Zeeman effect, diamagnetic term. At low temperature, the M(H) of Cu2O could be represented by spin polarization and Zeeman effect, then at high temperature, M(H) could be predominated by spin polarization and diamagnetic term. Looking the M(H) curve of CuO, it showed there were two components in the system at low temperature, spin polarization and Zeeman effect. M(H) was risen with magnetic field increasing at high temperature, there was other term in the system. By fitting Ms(T) and M(T),we observed that it had spin wave in the nanoparticle system. By the XRD patterns, we observed that Cu2O had a property of the negative thermal expansion at 150~180 K, and it had a relation with charge density transition.
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