Abstract:
We have investigated the effects of magnetic Fe ion substitution in Ce(Ru1−xFex)2Al10
on the magnetic and transport properties, when the Kondo insulator CeRu2Al10 with
anomalous antiferromagnetic order at TN = 27 K [1] is fully transformed into the
archetypal non-ordered Kondo insulator CeFe2Al10 [2]. The characteristic Kondo
temperature TK is determined from the magnetic susceptibility, and demonstrates a
linear dependence on Fe concentration between 0.6 and 1. With increasing x, the
positive maximum in the thermoelectric power just below TN enhances gradually and
reaches up to ∼80 µV/K (at T = 40 K) for x = 0.8, which is remarkably as high as ∼4
and ∼1.5 times the corresponding values in CeRu2Al10 and CeFe2Al10 respectively.
The magnitude of the lattice thermal conductivity is found to be nearly independent
of x, while the electronic thermal conductivity on the other hand decreases by an
order of magnitude when x increases from 0 to 0.8. We discuss our results in terms
of the extreme electronic sensitive nature between CeRu2Al10 and CeFe2Al10.
