Anisotropic Thermal Expansion and Field-Induced Structural Phase Transition in PrCu_<b>2</b>

Abstract

The Jahn-Teller effect and metamagnetic transition in single crystalline PrCu 2 have been studied by thermal expansion and magnetostriction measurements in the paramagnetic state. The linear thermal expansion in the temperature range from 1.8 to 300 K is found to be quite anisotropic in the whole temperature range, which is due to the highly anisotropic crystalline electric field. The magnetostrictions along the three crystallographic axes in the field along the c -axis also indicate anisotropic behavior with an extremely large length change and large hysteresis. It is clarified that the metamagnetic transition with the conversion of the Ising axis in PrCu 2 is due to the large modification of the crystalline electric field by the field-induced structural phase transition.