Activation Energies of Crystallization in Amorphous RMn4.5Ge4.5Fe1.5Al1.5 (R = La, Y, Dy) Alloys |
| Z. Śniadecki a, U.K. Rößler b and B. Idzikowski a
a Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland b IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany |
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| The effective activation energies, characteristic crystallization temperatures and enthalpies of amorphous RMn4.5Ge4.5Fe1.5Al1.5 (R = Y, La, Dy) alloys produced using melt-spinning technique were investigated by differential scanning calorimetry. X-ray diffraction measurements were performed for as-quenched and annealed samples. The crystalline structure of annealed YMn4.5Ge4.5Fe1.5Al1.5 and DyMn4.5Ge4.5Fe1.5Al1.5 alloys was determined as orthorhombic TbFe6Sn6-type with Cmcm (63) space group. The alloy with Y appears as a more useful non-magnetic analogue for DyMn4.5Ge4.5Fe1.5Al1.5 than the La-based alloy. The differential scanning calorimetry curves for Dy- and Y-based alloys also exhibit similar thermal behavior. The effective activation energies Ea were determined using the Kissinger approach and high values up to 778±74 kJ/mol for La-based sample were established. The comparison of Y-, La-, and Dy-based alloys suggests improvement of thermal stability with the increase in rare-earth element atomic radius in the glassy RMn4.5Ge4.5Fe1.5Al1.5 systems. |
| DOI: 10.12693/APhysPolA.115.409 PACS numbers: 61.43.Dq, 61.82.Bg, 75.50.Kj, 81.70.Pg |