Electrical transport, heat capacity, and high-field magnetization study in intermetallic Ni_2CeSn compound

摘要

Magnetization, heat capacity, and electrical resistivity measurements were performed on a Ni_2CeSn compound (orthorhombic structure) in the temperature range of 2-300 K. This compound is paramagnetic down to 6 K. At higher temperatures above T= 150 K, the magnetic susceptibility obeys Curie-Weiss behavior yielding an effective magnetic moment mu_(eff)=2.56 mu_B/f.u., which is very close to that of the free Ce~(3+) ion (2.54 mu_B) with a high negative Curie-Weiss temperature, THETA_(CW)=-170 K. As the temperature is decreased, the magnetic moment decreases gradually to 0.43 mu_B/f.u. at 4.2 K. We also infer that, based on the high field (up to 23 T) magnetization and the magnetic susceptibility data, a crystal-field splitting of cerium atoms becomes significant at temperatures below 150 K. We used heat capacity and resistivity measurements to determine the crystal-field splitting of the Ce~(3+) magnetic sublevels. It is found that the ground magnetic state for the Ce~(3+) is a doublet of J_z= +-1/2 states, with a first excited quartet of J_z= +- 3/2 and J_z= +-5/2 states separated by approx 107 K. The resistivity exhibits a shallow minimum at about UK, which may be due to the development of partial magnetic order based on these crystal-field-split states.