Thermal Expansion and Magnetostriction of the Ising Antiferromagnet TbNi2Ge2

TbNi$_{2}$Ge$_{2}$ has been shown to be an extremely anisotropic, axial, Ising-like antiferromagnet. In zero field it enters incommensurate and commensurate antiferromagnetic states at 16.7 K and 9.6 K respectively; six additional metamagnetic phases have been observed in applied fields at 2 K. In this talk we present preliminary measurements of the thermal expansion and magnetostriction of this material along its c-axis from room temperature to 2 K and in magnetic fields (H$\vert \vert $c) to 14 T. This work was supported by the Director for Energy Research, Office of Basic Energy Sciences, US DOE and was partially supported by the NSF under DMR-0305397.