Ferromagnetism in novel compounds of the R sub(3)Pt sub(23)Si sub(11 ) series with heavy rare earth: Gd, Tb, Dy, Ho and Er

• Published in: Journal of magnetism and magnetic materials 2014-05, Vol.357, p.13-17
• Main Authors: Opagiste, C, Galera, R M
• Format: Article
• Language: English
• Subjects: Constants; Diffraction; Dysprosium; Entropy; Erbium; Ferromagnetism; Rare earth metals; Reduction
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2014.01.010

We have synthesized new compounds of the R sub(3)Pt sub(23)Si sub(11 ) series with R = Gd, Tb, Dy, Ho and Er, and studied their magnetic and thermodynamic properties. X-ray powder diffraction characterization confirms that all these compounds crystallize in the same face-centered cubic structure, space group Fm3m, as Ce sub(3)Pt sub(23)Si sub(1 1). They all present a ferromagnetic order at low temperatures. The Curie temperatures range between 42 + or - 1 K and 3.39 + or - 0.05 K for Gd sub(3)Pt sub(23)Si sub(1 1) and Er sub(3)Pt sub(23)Si sub(1 1) respectively. For all compounds the value of the spontaneous moment at 2 K is far below the value expected for the saturated moment of the R super(3+) ions, except for the Gd compound. The estimations of the magnetic entropy at T sub()cremain smaller than the full entropy of the fundamental multiples R ln(2J + 1). Both reductions, of the moment and of the magnetic entropy, are ascribed to the crystal field effects. In the paramagnetic phase the thermal variation of the suceptibilities follows a Curie-Weiss law with Curie constants in good agreement with the theoretical values.