High-field magnetization of the triangular-lattice antiferromagnet Gd 1− xLa xPd 2Al 3

Abstract

We have grown Gd 1− x La x Pd 2Al 3 ( x<0.5) single crystals by the Czochralski pulling method to investigate the magnetic dilution effect on the triangular-lattice antiferromagnet GdPd 2Al 3. The B– x and T– x phase diagrams were determined by magnetic susceptibility and high-field magnetization measurements. The successive phase-transition temperatures T N1 and T N2 decrease linearly with increasing x and vanish above about x=0.8 and 0.55, respectively. When the field is applied along the c-axis, a 1 3 plateau of the full magnetic moments is clearly observed for x<0.25 at 2 K and disappears for x>0.4. We have discussed these experimental data by using the 2D triangular-lattice Heisenberg Hamiltonian with weak Ising-type anisotropy and the site percolation theory.