Annealing Effect on Microstructure and Coercivity of YCo5 Nanoparticles Obtained by Mechanical Milling

Abstract:

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Nanocrystalline YCo5 powders with high coercivity were prepared by mechanical milling and subsequent heat treatment at 820 °C for different annealing times, ta = 2.5, 3.0, 3.5 and 4.5 min, obtaining average crystallite sizes of  17, 19, 32 and 39 nm., respectively. The coercivity values were determined from the hysteresis loops measured at maxima fields of Hm = 5 and 20 T. The highest coercivity was obtained for the sample exhibiting  19 nm, where at room temperature and Hm = 5 T, the coercivity value is of 9.0 kOe. At 77 K and Hm = 5 T, the coercivity increase to 11.8 kOe and for Hm = 20 T, a higher value such as 13.1 kOe was found. The Ms/Mr ratio is enhanced to 0.62 indicating the occurrence of exchange interaction among nanocrystalline magnets.

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Periodical:

Edited by:

S. Velumani and René Asomoza

Pages:

122-126

DOI:

10.4028/www.scientific.net/AMR.68.122

Citation:

J. T. Elizalde Galindo et al., "Annealing Effect on Microstructure and Coercivity of YCo5 Nanoparticles Obtained by Mechanical Milling", Advanced Materials Research, Vol. 68, pp. 122-126, 2009

Online since:

April 2009

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$35.00

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