The Thermal Expansion of the Heavy Fermion Antiferromagnet YbAgGe

Abstract

We searched for evidence of quantum phase transitions in the heavy fermion antiferromagnet YbAgGe with high magnetic fields applied along the crystallographic c-axis. Using a capacitive dilatometer we measured the thermal expansion of the crystal in fixed magnetic fields ranging from 0T to 9T. With this information and recent magnetostriction data we created a phase diagram that shows two regions of magnetic order in the magnetic field-temperature plane. We discuss these results in light of recent work suggesting quantum phase transitions in this material.