CeNi^sub 3^-type rare earth compounds: crystal structure of R^sub 3^Co^sub 7^Al^sub 2^ (R=Y, Gd–Tm) and magnetic properties of {Gd–Er}^sub 3^Co^sub 7^Al^sub 2^, {Tb, Dy}^sub 3^Ni^sub 8^Si and Dy^sub 3^Co^sub 7.68^Si^sub 1.32

• Published in: Journal of magnetism and magnetic materials 2017-03, Vol.426, p.729
• Main Authors: Morozkin, AV, Yapaskurt, VO, Nirmala, R, Quezado, S, Malik, SK
• Format: Article
• Language: English
• Subjects: Alloys; Aluminum; Cobalt; Coercivity; Crystal structure; Dysprosium; Erbium; Ferromagnetism; Magnetic properties; Magnetism; Magnetization; Nickel; Rare earth compounds; Terbium; Trace elements
• ISSN: 0304-8853; 1873-4766

The crystal structure of new CeNi3-type {Y, Gd-Tm}3Co7Al2 (P63/mmc. N 194, hP24) compounds has been established using powder X-ray diffraction studies. The magnetism of Tb3Ni8Si and Dy3Ni8Si is dominated by rare earth sublattice and the magnetic properties of R3Co7Al2 (R =Gd-Er) and Dy3Co7.68Si1.32 are determined by both rare earth and cobalt sublattices. Magnetization data indicate ferromagnetic ordering of {Tb, Dy}3Ni8Si at 32 K and 21 K, respectively. Gd3Co7Al2 and Tb3Co7Al2 exhibit ferromagnetic ordering at 309 K and 209 K, respectively, whereas Dy3Co7Al2, Ho3Co7Al2, Er3Co7Al2 and Dy3Co7.68Si1.32 show a field dependent ferromagnetic-like ordering at 166 K, 124 K, 84 K and 226 K, respectively followed by a low temperature transition at 34 K for Dy3Co7Al2, 18 K for Ho3Co7Al2, 56 K for Er3Co7Al2, 155 K and 42 K for Dy3Co7.68Si1.32. Among these compounds, Dy3Ni8Si shows largest magnetocaloric effect (isothermal magnetic entropy change) of -11.6 J/kg.K at 18 K in field change of 50 kOe, whereas Tb3Co7Al2, Dy3Co7Al2 and Dy3Co7.68Si1.32 exhibit best permanent magnet properties in the temperature range of 2-5 K with remanent magnetization of 11.95 µB/fu, 12.86 µB/fu and 14.4 µB/fu, respectively and coercive field of 3.0 kOe, 1.9 kOe and 4.4 kOe, respectively.