ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Low-field susceptibility measurements show that Ce1−xGdxAl3 exhibits spin-glass-like behavior over nearly the entire concentration range. The temperatures of the spin-glass-like transition Tm(x) are surprisingly high [Tm(0.635)=125 K] considering that none of the rare-earth trialuminides order above 25 K. The Ce is necessary for the anomalous behavior since it is absent in (La, Gd)Al3. For x≤0.23, T≤5 K there is an interplay between the heavy-fermion and spin-glass-like behavior. The values of Tm would probably not be so large if the system were not a heavy-fermion system. On the other hand, the spin-glass-like transition appears to modify the heavy-fermion character of the specific heat. The large C/T values at low temperatures (410 mJ/mole K2 for x=0.26) probably would have been still larger if they were not reduced by the effective field of the spin-glass-like state. The low-field susceptibility measurements show spin-glass-like cusp anomalies for x=0.08, 0.15, 0.18, 0.20, 0.23, 0.34, 0.40, 0.635, 0.77, and 0.9. This anomaly in the susceptibility at Tm persists as one increases x through the antiferromagnetic percolation threshold at x≡xc ∼0.5. However, the magnitude of the susceptibility anomaly decreases two orders of magnitude as one increases x from 0.5 to 0.635. The resistivity in most respects resembles that of a dense Kondo system. It differs in that for x〉xc there is an additional amomaly in the resistivity at Tm, which is absent for x≤xc. The presence of this anomaly shows that the range of the order below Tm becomes at least as long as the mean free path for x〉xc. For x〉xc there are two transition observed in the susceptibility, the spin-glass-like transition at Tm and an antiferromagnetic transition at low temperatures. Specific heat measurements also show the antiferromagnetic transition.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.338543
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