Figure 1

(Color online) Magnetization loops of the $\mathrm{Co}∕\mathrm{Pt}$ dots for three different excursion fields measured at $5\mathrm{K}$. The insets show (a) an atomic force microscopy picture of the magnetic dots and (b) the remanent magnetization $M_0$ as a function of the maximum applied field $H_m$ starting from the demagnetized state ${\mu }_0{H}_m=0\mathrm{mT}$.Reuse & Permissions

Figure 2

(Color online) (a) Superconducting transition $T_c\left(H\right)$ of the Al film for different magnetic states of the dots. By increasing the magnetization a clear shift of $T_c\left(H\right)$ and a decrease of $T_c^{\mathit{max}}$ is observed. (b) Lateral dimension $w$ of the nucleation of superconductivity as a function of the magnetization of the dots.Reuse & Permissions

Figure 3

(Color online) (a) Magnetoresistance measurements for different values of the magnetization $M_0$ of the magnetic dots at a constant reduced temperature $t=T∕T_c$. The presented data correspond to the transition of the location of the maximum $T_c$ from $\varphi ={\varphi }_0$ to $2{\varphi }_0$. For clarity the curves have been displaced horizontally. (b) Illustration of the supercurrents encircling the magnetic dots as a function of the magnetization. Colored symbols correspond to the colored curves in panel (a). Starting from the black curve, the increase of the magnetization will result in increasing currents, counteracting the field of the dots and keeping the flux exactly equal to ${\varphi }_0$. Crossing a critical value $M_{c2}$ the currents reverse polarity hereby generating an extra vortex-antivortex pair. Further increasing the magnetization will result in a decrease of the currents since the flux is increasingly carried by the dot itself.Reuse & Permissions

Figure 4

Contour plot of the resistance as a function of field and magnetization for $t=0.991$. Dark islands correspond to lowest resistance and hence highest critical temperature. The steplike profile is a consequence of the quantization of the magnetic field in an integer number of flux quanta by the superconductor.Reuse & Permissions