Figure 1

Insets: the zero-field ac susceptibility, measured on warming following zero-field cooling, for (a) the $x=0.20$ and (b) the $x=0.21$ samples. The main body reproduces the effect of superimposed static fields of (a) 1.3 (top) to 4.8 kOe (bottom), and (b) 0.4 (top) to 0.9 kOe (bottom). (c)–(h) are double-log plots testing the 3 power-law predictions. The peak susceptibility (corrected for background and demagnetizing effects) against internal field, $H_i$, Eq. (1), for (c) $x=0.20$ and (d) $x=0.21$. The reduced peak temperature, $t_m$, against internal field, Eq. (2), for (e) $x=0.20$ and (f) $x=0.21$. The peak susceptibility against reduced temperature for (g) $x=0.20$ and (h) $x=0.21$. Estimates of the ordering temperature, $T_C$, used in (e), (f), (g), and (h), from plots of the susceptibility peak temperature, $T_m$, against $H_i^{0.57}$ (see text) for (i) $x=0.20$ and (j) $x=0.21$.Reuse & Permissions

Figure 2

An Arrott-Noakes representation of the magnetization data for (a) $x=0.20$ and (b) $x=0.21$ using Heisenberg model exponents. Magnetization along the critical isotherms for (c) $x=0.20$ and (d) $x=0.21$. Scaling curves for (e) $x=0.20$ and (f) $x=0.21$.Reuse & Permissions

Figure 3

(a) The inverse dc susceptibility, $H/M$, measured in 100 Oe, and (b) the inverse, zero-field ac susceptibility as a function of temperature for the $x=0.21$ single crystal. The insets show double-log plots testing the power-law relationship, Eq.. (4), with $t=(T-T_C^R)/T_C^R$ and $T_C^R=210\mathrm{K}$ (a) and 209 K (b). The corresponding estimates for λ are shown. (c) corresponds to inverse susceptibility data for $x=0.20$: main figure, ac susceptibility; inset, dc data.Reuse & Permissions

Figure 4

The temperature dependence of the resistivity, $\rho$, in applied fields from 0 T (top), 2 T, 3 T, 5 T, 7 T, to 9 T (bottom) for (a) $x=0.20$ and (b) $x=0.21$. The insets show the fractional magnetoresistance.Reuse & Permissions

Figure 5

The low temperature spontaneous magnetization $M/M_0$, plotted against $T^{3/2}$. The slope of these plots yield values for the acoustic spin-wave stiffness of (a) $D=65\mathrm{meV}{\AA }^2$, $x=0.20$ and (b) $D=120\mathrm{meV}{\AA }^2$, $x=0.21$.Reuse & Permissions