1307.4271 (J. O. Piatek et al.)

Phase diagram with enhanced spin-glass region of mixed Ising / XY
magnets LiHo$_{x}$Er$_{1-x}$F$_{4}$    [PDF]

J. O. Piatek, B. Dalla Piazza, N. Nikseresht, N. Tsyrulin, I. Živković, K. W. Krämer, M. Laver, K. Prokes, S. Mataš, N. B. Christensen, H. M. Rønnow

We present the experimental phase diagram of LiHo$_x$Er$_{1-x}$F$_4$, a dilution series of dipolar-coupled model magnets.The phase diagram was determined using a combination of AC susceptibility and neutron scattering. Three unique phases in addition to the Ising ferromagnet LiHoF$_4$ and the XY anti-ferromagnet LiErF$_4$ have been identified. Below $x=0.86$ an embedded spin-glass phase is observed, where a spin-glass exists within the ferromagnetic structure. Below $x=0.57$ an Ising spin-glass is observed consisting of frozen needle-like clusters. For $x \sim 0.3 - 0.1$ an antiferromagnetically coupled spin-glass occurs. A reduction of $T_C(x)$ for the ferromagnet is observed which disobeys the mean-field predictions that worked for LiHo$_x$Y$_{1-x}$F$_4$.

View original: http://arxiv.org/abs/1307.4271