Exchange-biasing mechanism in La2/3Ca1/3MnO3/La1/3Ca2/3MnO3 multilayers

A series of [La2/3Ca1/3MnO3(Lambda/2)/La1/3Ca2/3MnO3(Lambda/2)](15) multila yers, with bilayer thicknesses Lambda between 2 and 32 nm, has been prepare d by pulsed laser deposition. The study of their magnetic and magnetotransp ort properties reveals the presence of an exchange-biasing mechanism at low temperatures. Zero-field-cooling and field-cooling magnetic measurements r eveal a blocking temperature :around 70 K that is independent from the bila yer thickness, whereas the average film magnetization becomes zero at 250 K . It is observed that the exchange-biasing field H-EB at 10 K follows the v ariation of coercive field H-c with Lambda, indicating that there is a sign ificant contribution in H-c from the exchange anisotropy at the interfaces. The optimum exchange-biasing properties were observed in multilayers with Lambda = 8 nm. [S0163-1829(99)04525-7].