Crystal electric field and quadrupole ordering in semiconducting PrPtBi

We prepared PrPtBi crystal by tungsten crucible and carried out inelastic n eutron and thermal expansion experiments together with transport properties . The crystals show semiconducting properties both in electrical resistivit y and Hall constant. As for crystal electric field (CEF), the results show that the CEF level scheme consists of non-Kramer's doublet Gamma(3) ground state, a first excited state Gamma(5) with an energy of 75 K, a second exci ted one Gamma(4) with an energy of 116 K. Precise experiment of thermal exp ansion under the magnetic field suggests that the phase transition at 1.35 K is of a ferroquadrupolar-type. (C) 2000 Elsevier Science B.V. All rights reserved.