| Summary: | 碩士 === 中華技術學院 === 機電光工程研究所碩士班 === 97 === Abstract
This work uses hydrothermal method to grow up MnxZn1-xF2O4 magnetic nanopowders. At first, MnCl2, ZnCl2, FeCl3 as the raw materials and mineralizer Na2CO3, NaOH are put into the autoclave at 170 and 200℃with high pressure. The Mn-Zn ferrites are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and SQUID. The XRD results show that the synthesized ferrites with mineralizer Na2CO3 can not have a completed reaction and crystalline. Nevertheless, the mineralizer is NaOH that can make a great reaction and show spinel structure. MnxZn1-xF2O4 magnetic nanopowders show good crystalline and bigger grain size with the Mn+2 concentration increasing. The powders morphology can be observed by the SEM that show aggromeration and abnormal grain phenomenon with the mineralizer Na2CO3. Moreover, the cubic grain can be obtained with NaOH, 170℃ with Mn0.8Zn0.2F2O4. From the Raman spectroscopy, the samples with Na2CO3 at x=0.8 shows the peak at the 606 cm-1. The peak at the 651cm-1 (x=0) will decrease with increasing Mn concentration to the peak at the 603 cm-1 (x=1). From SQUID results, Mn0.8Zn0.2F2O4 (x=0.8) reveals the best magnetization with the mineralizer NaOH. The magnetization increases with the Mn+2 concentration increasing. The Mn+2 ion is the key point to affect the Mn-Zn ferrites magnetic quality。
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