Elsevier, Journal of Alloys and Compounds, 1(508), p. 28-36
DOI: 10.1016/j.jallcom.2010.08.059
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The ternary intermetallic compound EuCu9Mg2 has been synthesized. The magnetic properties have been investigated by magnetization measurements and 151Eu Mössbauer spectroscopy. Europium is divalent and a spin freezing is observed at 25 K. However, this spin freezing is characterized by the onset of strong magnetic irreversibility, which suggests a cluster glass freezing. The Mössbauer spectra can be analyzed as the superposition of two sub-spectra of Eu2+ ions, which is consistent with a cluster glass freezing. A transition to the ferromagnetic state is induced by application of a magnetic field the order of 0.5 Tesla. This anomalous feature is attributed to quantum spin fluctuations that oppose the long-range ferromagnetic ordering, due to the two-dimensional topology of the geometric arrangement of the Eu2+ ions. This 2D-topology is also evidenced by a quadratic variation of the specific heat as a function of temperature down to 2.7 K. The electrical resistivity is also analyzed in the framework of intermetallic compounds dominated by ferromagnetic spin fluctuations above the spin freezing temperature.