Crystalline electrical field effects on powdered RE Cu4Al8 (RE = Tb, Dy, Ho and Er) intermetallic compounds. (March 2021)

• Record Type: Journal Article
• Authors: Mercena, S.G.; Silva, L.S.; Lora-Serrano, R.; Garcia, D.J.; Souza, J.C.; Pagliuso, P.G.; Duque, J.G.S.
• Is Part Of: Intermetallics. Volume 130(2021)
• Publication Date: 2021-03
• Subjects: Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2020.107040
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: In this work, structural and magnetic properties R E Cu4 Al8 ( R E = Tb, Dy, Ho and Er) family of compounds are reported. Measurements of X-ray diffraction, temperature ( T ) and magnetic field ( H ) dependencies of magnetization are presented for each compound. The analysis of X-ray diffraction patterns shows a small variation in a (8.705824–8.734991 Å ) and c (5.123802–5.135258 Å ) lattice parameters as a function of the rare earth. The T -dependent magnetic susceptibility reveals the Curie-Weiss-like behavior at high- T evolving to antiferromagnetic transitions at low- T (6 < T N < 28 K) for all studied materials. Measurements of magnetization as a function of magnetic field show field-induced transitions for R E = Dy, Ho and Er, which present larger magnetic moments, though no magnetic saturation is attained (4.4 < M m a x < 7.3 μ B ) for none of the studied compounds. This fact is an indicative of strong crystalline electrical field (CEF) effects. We have conducted a detailed analysis, based on a mean-field spin model, in order to determine the CEF parameters from the macroscopic data of the studied powdered samples. Finally, to show the reliability of our calculations, the obtained CEF energy levels and wave functions are compared with previous CEF studies in single crystalline samples of ErCu4 Al8, including results obtained from inelastic neutron scattering data. Highlights: The single crystals of RE Cu4 Al8 ( RE = Tb, Dy, Ho and Er) were grown using the metal flux technique. All the characterizations presented (structural and magnetic) were carried out on the samples in the form of powder. The susceptibility behavior as a function of temperature shows well-defined magnetic transitions at low temperature and Curie-Weiss type behavior at high temperatures. Magnetization measurements as a function of the applied magnetic field do not show saturation effects up to the maximum measured field. Through simulations of the magnetization experimental data it was possible to extract information about the crystalline electric field and the exchange parameters involved.