Evidence for a non-magnetic Kondo effect in the structurally disordered UAsSe ferromagnet

Specific heat and thermal expansion measured along the c-axis are reported for the UAsSe single crystals with T-C = 101.5 K, which display the pronoun ced low-T upturn in the electrical resistivity. Besides the ferromagnetic t ransition, no additional anomaly has been found that could affect the low-T physics of UAsSe. The investigated Se-77 NMR spectra give evidence for a s ystematic development of the disorder caused by a small change of the sampl e composition. The appearance of electron-assisted tunneling of the atoms i n UAsSe and related compounds is discussed.