Crystal structure and anisotropic magnetic properties of new ferromagnetic Kondo lattice compound Ce(Cu,Al,Si)2

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:426

Article

Maurya, A.¹  Thamizhavel, A.¹  Dhar, S. K.¹  Provino, A.^2,3  Pani, M.^2,3  Costa, G. A.^2,3 

[1] Tata Inst Fundamental Res, Dept Condensed Matter Phys & Mat Sci, Homi Bhabha Rd, Bombay 400005, Maharashtra, India

[2] Univ Genoa, Dept Chem, Via Dodecaneso 31, I-16146 Genoa, Italy

[3] Inst SPIN CNR, Corso Perrone 24, I-16152 Genoa, Italy

关键词: Ce(Cu,Al,Si)(2);    Single crystal;    Ferromagnetic Kondo lattice;    Heavy fermion;    Crystal electric field;   

DOI  :  10.1016/j.jmmm.2016.11.078

来源: Elsevier

【 摘 要 】

Single crystals of the new compound CeCu0.18Al0.24Si1.58 have been grown by high-temperature solution growth method using a eutectic Al-Si mixture as flux. This compound is derived from the binary CeSi2 (tetragonal alpha-ThSi2-type, Pearson symbol tI12, space group I4(1)/amd) obtained by partial substitution of Si by Cu and Al atoms but showing full occupation of the Si crystal site (8e). While CeSi2 is a well-known valence-fluctuating paramagnetic compound, the CeCu0.18Al0.24Si1.58 phase orders ferromagnetically at T-C=9.3 K. At low temperatures the easy-axis of magnetization is along the alpha-axis, which re-orients itself along the c-axis above 30 K. The presence of hysteresis in the magnetization curve, negative temperature coefficient of resistivity at high temperatures, reduced jump in the heat capacity and a relatively lower entropy released up to the ordering temperature, and enhanced Sommerfeld coefficient (approximate to 100 mJ/ mol K-2) show that CeCu0.18Al0.24Si1.58 is a Kondo lattice ferromagnetic, moderate heavy fermion compound. Analysis of the high temperature heat capacity data in the paramagnetic region lets us infer that the crystal electric field split doublet levels are located at 178 and 357 K, respectively, and Kondo temperature (8.4 K) is of the order of T-C in CeCu0.18Al0.24Si1.58.

【 授权许可】

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