Electron-quasiparticle interaction in DyNi2B2C measured by point-contact spectroscopy

The electron-quasiparticle interaction (EQI) spectral function has been mea sured for DyNi2B2C in the normal state at low temperatures by means of poin t-contact spectroscopy (PCS). A low-frequency peak is found around eV simil ar to 5 meV. It becomes measurable at T-m* similar or equal to 15 K and gro ws in intensity with constant width as the temperature is lowered. We argue that this peak arises from the strong interaction of conduction electron w ith coupled crystal-electric-field-phonon excitations whose branches cross at low energy. The comparison with PC spectra for HoNi2B2C suggests that a similar peak also exists for this compound. The magnitude of the point-cont act EQI parameter lambda(PC) for DyNi2B2C is estimated. (C) 2000 Elsevier S cience B.V. All rights reserved.