Exchange biasing and low-field magnetoresistance inLa0.67Ca0.33MnO3/La0.5Ca0.5MnO3bilayers

Exchange biasing and magnetoresistance (MR) behaviors have been investigated in La0.67Ca0.33MnO3/La0.5Ca0.5MnO3 bilayers with specially designed interfacial structures. The exchange coupling is found to be strongly related to interfacial structures. Exchange field H-E decreases as the cooling field N-fc increases at high H-fc region. Especially, the coercivity H-C is enhanced by exchange coupling for bilayers with rough interface, while it is reduced for relatively smooth interface. Also, large low-field MR has been achieved by introducing regular in-plane grain boundaries, and a biasing of R-H loop has been observed.