کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
11015789 | 1781703 | 2019 | 38 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Anomalous specific heat and magnetic properties of TmxDy1-xAl2 (0 â¤Â x ⤠1)
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
فلزات و آلیاژها
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We study crystal structure, phase transitions and magnetism of pseudo-binary TmxDy1-xAl2 (0â¯â¤â¯xâ¯â¤â¯1) compounds using temperature dependent X-ray powder diffraction, specific heat and magnetization measurements, first principles, and model calculations. In low external magnetic fields, Dy-rich compounds undergo continuous, second-order phase transitions at the respective Curie temperatures, TC. In contrast, the Tm-rich compounds exhibit discontinuous, first-order anomalies in the magnetically ordered states. These sharp transitions correlate with a substantial energy difference between the room temperature cubic and ground state rhombohedral structures of TmAl2. A clear anomaly in the lattice parameter is observed at â¼30â¯K for xâ¯=â¯0.5, which nearly coincides with TCâ¯=â¯31.2â¯K. The effective quadrupolar moment of the lanthanides changes sign around xâ¯=â¯0.5, which leads to a nearly zero anisotropy constant and approximately spherical effective 4f charge densities, providing an explanation for the lack of structural distortions below TC for xâ¯=â¯0.5. The calculations confirm [001] as the easy magnetization axis in the ground state tetragonal structure of DyAl2, and reveal collapse of the orbital magnetic moment when the easy magnetization direction changes to [111]. Within the rhombohedral ground state of TmAl2 [111] is the easy magnetization direction.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Alloys and Compounds - Volume 774, 5 February 2019, Pages 321-330
Journal: Journal of Alloys and Compounds - Volume 774, 5 February 2019, Pages 321-330
نویسندگان
Arjun K. Pathak, C.M. Bonilla, D. Paudyal, Y. Mudryk, V.K. Pecharsky,