CeCu4Al and CeCu2Zn2Al: Very heavy fermion systems in high magnetic fields

摘要

CeCu(sub 4)Al and CeCu(sub 2)Zn(sub 2)Al are heavy fermion systems with extremely enhanced C/T (specific heat divided by temperature) values of 2.3 and 1.8 J/K(sup 2) respectively as T -> 0 K. The field dependence of the low temperature specific heat is also extreme; 11 T reduces C of CeCu(sub 4)Al by more than a factor of five, 12.5 T suppresses C of CeCu(sub 2)Zn(sub 2)Al about seven times. Magnetic field caused changes of the specific heat of CeCu(sub 4)Al are consistent with a single ion Kondo model. Magnetic correlations are at least partially responsible for the enhanced low temperature specific heat of CeCu(sub 2)Zn(sub 2)Al.