Design of a metallic Ising spin glass in the Y1-xTbxNi2Ge2 system

Abstract

There has been much interest in the past ten years in the effects of applying a transverse magnetic field on the freezing temperature of Ising spin glasses. The focus of this study is to search for and characterize a metallic Ising spin-glass system. This is accomplished by site diluting yttrium for terbium in the crystalline material TbNi2Ge2. Pure TbNi2Ge2 is an Ising antiferromagnet with several distinct magnetic states below 17 K. As the terbium is diluted with yttrium, magnetic coupling and ordering temperatures are suppressed in a monotonic way, as is seen in measurements of the transition temperatures and analysis of the high-temperature Curie-Weiss behavior. At low concentrations of terbium, below x similar to 0.35, long-range order is no longer detected and a spin-glass-like state emerges. This state is studied through a variety of measurements: dc and ac susceptibility, resistivity, and specific heat. These data are then compared to that of other well characterized spin-glass systems. It is concluded that there is a region of concentrations for which an Ising spin-glass state is formed with the best spin glasses existing for x<~0.30.