The effect of interface roughness on exchange bias in La0.7Sr0.3MnO3 -   BiFeO3 heterostructures
  We characterized the interfaces of heterostructures with different stack sequences of La0.7Sr0.3MnO3/BiFeO3 (LSMO/BFO) and BFO/LSMO using TEM revealing sharp and rough interfaces, respectively. Magnetometry and magnetoresistance measurements do not show a detectable exchange bias coupling for the multistack with sharp interface. Instead, the heterostructures with rough and chemically intermixed interfaces exhibit a sizable exchange bias coupling. Furthermore, we find a temperature-dependent irreversible magnetization behavior and an exponential decay of coercive and exchange bias field with temperature suggesting a possible spin-glass-like state at the interface of both stacks. 
Mehran Vafaee, Simone Finizio, Hakan Deniz, Dietrich Hesse, Hartmut   Zabel, Gerhard Jakob, and Mathias Kl\"aui
cond-mat.str-el