Figure 5

(a,b) Hysteresis loops for the [Dy₆/Fe₆]₁₀ sample at various temperatures after field cooling in 50 kOe from 300 K. The loops are corrected for their diamagnetic contributions. (c) The plot of H_c and H_eb (negative bias) for the [Dy₆/Fe₆]₁₀ and [Dy₁₂/Fe₆]₁₀ samples at various temperatures. The inset shows a plot of H_c versus T^1/2 with two different slopes.