EFFECTS OF ZN DOPING ON LATTICE SPECIFIC-HEAT IN LA2CUO4

Specific heat of La2Cu1-yZnyO4 samples with y = 0, 0.04, 0.06 and 0.10 has been measured between 1.5 and 7 K. It has been observed that latt ice specific heat of the samples has a higher-order term as well as a term in T-3 in the temperature range investigated. The results have be en reproduced by the addition of an Einstein term to the T-3 one. The latter contribution is essentially independent of Zn doping. Since Zn atom has mass similar to Cu atom, acoustic modes with long wavelength will not be affected. The former contribution, on the other hand, grow s with increasing Zn content.