Synthesis and magnetic properties of Chromium-dopednickel ferrite nanoparticles

• Main Authors: Yueh Ting Lin, 林岳廷
• Other Authors: 林儒禮
• Format: Others
• Language: zh-TW
• Published: 103
• Online Access: http://ndltd.ncl.edu.tw/handle/x6cq8s

碩士 === 南台科技大學 === 機械工程系 === 102 === In the vicinity of the magnetic compensation points, at which the condition is realized for the vanishing of the resultant magnetization, is a rather interesting terrain for magnetic property research. As far as we known, there are no reports of the particle size effects on the magnetic compensation point transition of spinel nanoparticles (NPs). It is known that chromium doped the iron-containing spinel ferrites will be induced a compensation point transition. In this work, NiFe0.75Cr1.25O4 NPs with mean crystallite sizes (d) ranging from 4.5 to 47.7 nm were synthesized by the combustion method. The NPs with d ≥ 11.7 nm show compensation below the Curie temperature TC , while the NPs with d = 4.5 nm did not exhibit the compensation transition. The compensation temperatures Tcomp , determined from the zero-field-cooled (ZFC) and field-cooled (FC) magnetization, are between 345 K and 370 K. The NPs with d ≤ 11.7 nm show a superparamagnetic behavior above Tcomp . Moreover, the NPs with d ≥ 33.9 nm display that the ZFC magnetization is higher than the FC magnetization below the Tcomp .