The research on the fabrication and physical properties of CeAl4 nanoparticles

• Main Authors: Frank fon ching hwang, 黃豐欽
• Other Authors: C.R.Wang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/60500725141189352682

碩士 === 東海大學 === 物理學系 === 94 === The bulk CeAl4 undergoes a ferromagnetic transition at TC = 6.2 K, follow by an antiferromagnetic ordering at TN = 3.2 K . The CeAl4 nanoparticles was fabricated by pulsed-laser deposition methods.By controlling carefully the conditions , including gas pressures , laser power and temperature of substrate, the CeAl4 nanoparticles were fabricated with sizes between 10 and 30 nm .No impurity phase can be detected by X-ray diffraction patterns . The magnetic behavior of nanoparticles have been measured by SQUID between 2 K and 300 K.We find that when the particles’ size was reduced , the antiferromagnetism will be depressed . A typical behaviors of superparamagnetism below 6 K . show that the sample remain on ferromagnetic state . The small curie constant of nanoparticles , which was fabricated under 0.02 torr He gas ,was about 33% of the bulk . This imply that a certain degrees of demagnetization of Ce ions in nanoparticles .