Structure and magnetic properties of nanocrystalline dysprosium powders
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In this current study, nanocrystalline Dy powders were prepared by melt-spinning and subsequent high-energy ball-milling. The effect of ball-milling time on the structure and magnetic properties of the powders was studied. The crystal structure and microstructure of the melt-spun ribbons and ball-milled powders were observed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Magnetic measurement of all samples was performed with vibrating sample magnetometer (VSM). XRD results indicate that the average crystal grain size of the powders decreases from 90.09 nm of the ribbons to 10.42 nm of the 4-h ball-milled powders. Further TEM observation shows that the grains are fine and uniform. The Neel temperature (TN) decreases from 182 K of the ribbons to 172 K of the powders, while the Curie temperature (TC) increases from 100 to 130 K, demonstrating that the grain size has substantial influence on the magnetic transition process. Moreover, at 60 K, as the ball-milling time increases, the coercivity of the powders increases first, peaking at 0.48 T for 2-h milling, then drops again, while the remanence of the powders decreases monotonically. As a result, the powders milled for 2 h exhibit an optimal maximum energy product of 64.0 kJ·m−3, demonstrating the good potential of these powders as a permanent magnet at low temperatures.
KeywordsDysprosium Nanocrystalline Low temperature Magnetic properties
This work was financially supported by the National Natural Science Foundation of China (Nos. 51401001, 51701109 and 51331003) and the International S&T Cooperation Program of China (No. 2015DFG52020).
- Wang HY, Pan JF, Wang Y, Jiang MQ, Liu XC, Pan J. Orientation degree and coercive force mechanism of die-upset (Nd, Pr)-Fe-Nb-B magnets. Chin J Rare Met. 2017;41(6):641.Google Scholar
- Zhu K, Hou YL. Controllable synthesis of rare-earth based permanent magnetic nanomaterials and their magnetic properties. Chin J Rare Met. 2017;41(5):466.Google Scholar
- Hannachi E, Slimani Y, Ben Salem MK, Hamrita A, Al-Otaibi AL, Almessiere MA, Ben Salem M, Azzouz FB. Fluctuation induced conductivity studies in YBa2Cu3Oy compound embedded by superconducting nanoparticles Y-deficient YBa2Cu3Oy: effect of silver inclusion. Indian J Phys. 2016;90(9):1009.CrossRefGoogle Scholar
- Slimani Y, Hannachi E, Hamrita A, Ben Salem MK, Ben Azzouz F, Manikandan, Ben Salem M. Comparative investigation of the ball milling role against hand grinding on microstructure, transport and pinning properties of Y3Ba5Cu8O18±δ and YBa2Cu3O7-δ. Ceram Int. 2018;44(16); 19950.Google Scholar
- Kwon HWLJ, Yu JH. Coercivity of Nd–Fe–B-type fine particles prepared by mechanical milling of HDDR material. IEEE Trans Magn. 2013;50(1):2100604.Google Scholar
- Liu FY, Hou BH, Yue M, W KJ. Magnetic phase transition of nanocrystalline bulk metal gadolinium and dysprosium. J Chin Rare Earth Soc. 2011;29(1):36.Google Scholar