Exchange bias (EB) shifts are commonly reported for the ferromagnetic (FM)/antiferromagnetic (AFM) bilayer systems. While stoichiometric ordered Sm 2 NiMnO 6 (SNMO) and BaTiO 3 (BTO) are known to possesses FM and diamagnetic orderings respectively, here we have demonstrated the cooling field dependent EB and training effects in epitaxial SNMO/BTO/SNMO (SBS) heterostructure thin films. The polarized Raman spectroscopy and magnetometric studies reveal the presence of anti-site cation disorders in background of ordered lattice in SNMO layers, which introduces Ni-O-Ni or Mn-O-Mn local AFM interactions in long range Ni-O-Mn FM ordered host matrix. We have also presented growth direction manipulation of the degree of cation disorders in the SNMO system. Polarization dependent X-ray absorption measurements, duly combined with configuration interaction simulations suggest charge transfer from Ni/Mn 3d to Ti 3d orbitals through O 2p orbitals across the SNMO/BTO (SB) interfaces, which can induce magnetism in the BTO spacer layer. The observed exchange bias in SBS heterostructures is discussed considering the pinning of moments due to exchange coupling at SB (or BTO/SNMO) sandwich interface.The exchange bias (EB) phenomenon, described as the shift of isothermal magnetic hyteresis loop in the magnetic field scale, is attributed to unidirectional anisotropy effect [1,2].Ideally an antiferromagnetic (AFM) system possess equivalent energies for the two oppositely aligned magnetic sublattices. Now, the EB effect can be understood considering the exchange coupling of any one AFM sublattice spins with adjacent ferromagnetic (FM) spin arrangements, when the FM/AFM interface system (FM T C > AFM T N