Raman scattering investigation on YbPd

Raman spectra of the single crystal of YbPd have been measured in the temperature range from 4 K to 300 K. In this temperature range, YbPd undergoes two transitions at T₁ = 132 K and T₂ = 110 K. At 4 K, two new peaks have been observed, and the peak P2 at 91 cm^-1 have been found up to 120 K. This result indicates the structural distortion below T ₁. The energy and linewidth of P2 have been examined below 120 K. Its energy shows the minimum around 90 K and increases with increasing temperature up to T₂. The anomalous energy change below 90 K can be explained by the temperature dependence of the volume change. The steep change of the energy around T₂ is due to the structural change through the first order transition at T₂. The anomalous increase of the linewidth has been also observed below 20 K.