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Title: Reducing the ordering temperature of CoPt nanoparticles by B additive

We reported the effect of boron addition on magnetic properties and structure of CoPt nanoparticles prepared by a polyol method. The magnetic property measurement showed that the CoPt-B sample exhibited a much larger coercivity compared to the sample without B additive at the same annealing temperature. Transmission electron microscopy and energy dispersive X-ray spectroscopy revealed that the average particle size was about 2 nm for the as-synthesized sample with the ratio of Co and Pt close to 1:1. After annealing, the particle sizes increased but the composition was maintained. The phase transformation of the nanoparticles versus temperature was investigated using a combination of X-ray diffraction and in-situ X-ray absorption analysis. It was shown that the phase transition temperature at which the nanoparticles change from the disordered A1 phase to the ordered L1{sub 0} phase occurs at temperature of 600 °C. We concluded that boron additives could reduce the ordering temperature of CoPt of about 100 °C.
Authors:
 [1] ; ;  [2] ;  [3] ;  [3] ;  [4]
  1. Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand)
  2. Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand)
  3. (Thailand)
  4. School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)
Publication Date:
OSTI Identifier:
22314556
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 5; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABSORPTION; ADDITIVES; ANNEALING; BORON ADDITIONS; COERCIVE FORCE; COMPARATIVE EVALUATIONS; MAGNETIC PROPERTIES; NANOPARTICLES; PARTICLE SIZE; PHASE TRANSFORMATIONS; TRANSITION TEMPERATURE; TRANSMISSION ELECTRON MICROSCOPY; X RADIATION; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY