SPIN-GLASS BEHAVIOUR OF NOVEL TERNARY URANIUM ALUMINIDE U3Co4 +xAl12-x (x=0.55)
Résumé
Abstract Experimental results on dc and ac susceptibility, magnetization and magnetic relaxation, specific heat, electrical resistivity and magnetoresistivity up to 8 T are reported for the novel ternary uranium aluminide U3Co4.55Al11.45. The temperature dependence of the dc susceptibility shows a cusp at a characteristic temperature Tf = 8-10 K that depends weakly on the applied magnetic field. The observed pronounced difference between the ZFC and FC magnetization, as well as the decay in the remanence both give evidence that a highly irreversible, frozen state is formed below Tf which is reminiscent of spin-glass behaviour. The real and imaginary parts of the ac-susceptibility show the corresponding Tf peaks being only slightly dependent on frequency. Electrical resistivity measured at zero and in fields up to 8 T indicates that the Kondo-like state becomes dominant at temperatures above Tf.
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