Exchange Bias Effect along Vertical Interfaces in La_0.7Sr_0.3MnO₃:NiO Vertically Aligned Nanocomposite Thin Films Integrated on Silicon Substrates

Silicon (Si) integration is a critical step toward future applications of multifunctional oxides as nanoscale electronics and spintronic devices, because of the low cost and scalability of silicon substrates. As a demonstration, self-assembled (La_0.7Sr_0.3MnO₃)_<i>x</i>: NiO_1–<i>x</i> (LSMO:NiO) vertically aligned nanocomposite (VAN) thin films with exchange bias (EB) properties have been successfully deposited on buffered Si substrates. To enable the epitaxial growth of LSMO:NiO VAN, SrRuO₃/TiN was first grown as the buffer layers on Si substrates. The composition of the two-phases has been varied with <i>x</i> = 0.25, 0.5, 0.75, and 1 to explore the electrical transport and magnetic properties of the VAN system on Si. The irreversible temperature <i>T</i>_irr was found to increase with increasing NiO composition, with the highest for (LSMO)_0.25­(NiO)_0.75 of ∼275 K, when the field was applied in the out-of-plane direction. In addition, the EB effect has been observed for all the nanocomposite films, with the highest <i>H</i>_EB value of 300 Oe for (LSMO)_0.25­(NiO)_0.75. The integration of the VAN system on Si with pronounced EB properties presents a promising approach toward future practical devices using oxide VANs on Si