Exchange-biasing mechanism in ${\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_3/{\mathrm{La}}_{1/3}{\mathrm{Ca}}_{2/3}{\mathrm{MnO}}_3$ multilayers

A series of $\left[{\mathrm{La}}_{2/3}{\mathrm{Ca}}_{1/3}{\mathrm{MnO}}_3\right(\Lambda /2)/{\mathrm{La}}_{1/3}{\mathrm{Ca}}_{2/3}{\mathrm{MnO}}_3(\Lambda /2){]}_{15}$ multilayers, with bilayer thicknesses $\Lambda$ between $2$ and 32 nm, has been prepared by pulsed laser deposition. The study of their magnetic and magnetotransport properties reveals the presence of an exchange-biasing mechanism at low temperatures. Zero-field-cooling and field-cooling magnetic measurements reveal a blocking temperature around 70 K that is independent from the bilayer thickness, whereas the average film magnetization becomes zero at 250 K. It is observed that the exchange-biasing field $H_{\mathrm{EB}}$ at 10 K follows the variation of coercive field $H_c$ with $\Lambda ,$ indicating that there is a significant contribution in $H_c$ from the exchange anisotropy at the interfaces. The optimum exchange-biasing properties were observed in multilayers with $\Lambda =8\mathrm{}\mathrm{nm}.$