Figure 1

Magnetization ($M$) as a function of field ($H$) for various doping ($x$) levels for ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$. The arrows indicate the trajectories followed in changing the applied field. Data for $x=0.03$ and 0.15 are for single crystals with $H\parallel ab$. All other hysteresis data are for polycrystalline samples. The insets for $x=0.07$, 0.10, and 0.17 depict data at higher fields. The plots for $x=0.05$, 0.07, 0.10, and 0.15 include characteristic data for the virgin curves (the center curve, in red online). The lowest panel depicts the doping dependence of the coercive field (circles) and the normalized hysteresis width at the origin (squares).Reuse & Permissions

Figure 2

Magnetic loops performed on the virgin curve for ${\mathrm{La}}_{1.9}{\mathrm{Sr}}_{0.10}{\mathrm{CuO}}_4$ (polycrystal) and ${\mathrm{La}}_{1.9}{\mathrm{Sr}}_{0.15}{\mathrm{CuO}}_4$ (single crystal). (a) The main plot shows a set of subloops for $x=0.10$ performed on the virgin curve at $T=45\mathrm{K}$. The arrows denote the trajectories followed around the various loops. The lower inset compares the two subloops ($A$ and $B$) shown on the main panel which were taken between the same applied field end points at $T=45\mathrm{K}$. The upper inset shows subloops obtained the same way as in the lower inset but at $T=300\mathrm{K}$. The subloops in the insets have been shifted to zero for comparison. (b) Low-field $M(H)$ for an $x=0.15$ single crystal ($T_c=37.5\mathrm{K}$, $m=1.1\mathrm{mg}$). Main panel: comparison of subloops performed on the virgin curve at $T=70\mathrm{K}$ the same way as for $x=0.10$. The trajectories followed, as well as the shading (colors online) and symbols are in accordance with panel (a). The inset depicts the subloops performed on the virgin curve at $T=275\mathrm{K}$.Reuse & Permissions

Figure 3

Doping dependence of the onset temperature $T_{\mathrm{onset}}$ (filled circles, blue online) of the normal state magnetic order and the superconducting transition temperature $T_c$ (open circles, black line) in ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_x{\mathrm{CuO}}_4$. Data for $x=0.03$ and 0.15 are for single crystals with $H\parallel ab$.Reuse & Permissions