In this paper, we fabricated graphene/Fe₃O₄ heterostructure devices by stacking monolayer graphene on magnetite (Fe₃O₄) substrate and investigated their magneto-transport properties. Interestingly, graphene/Fe₃O₄ heterostructure devices exhibit a giant magnetoresistance (MR) of 70% at a low magnetic field of 0.65$$T and at 11$$K, which is three times greater than that of graphene on SiO₂. Based on standard two-fluid model and LDA$+$U simulation, we showed that the observed enhanced MR effect is due to the increased disorder in graphene induced through the charge polarization via the alignment of C atoms of graphene over the charge ordered B-site cations of Fe₃O₄. Our results demonstrate a potential way to enhance graphene MR effect through coupling graphene with a suitable substrate with charge orbital ordering.

在本文中，我们通过在磁铁矿（Fe ₃ O _{4 ）衬底上堆叠单层石墨烯制备了石墨烯/Fe 3} O ₄异质结构器件，并研究了它们的磁传输特性。有趣的是，石墨烯/Fe ₃ O ₄异质结构器件在 0.65 的低磁场下表现出 70% 的巨磁阻 (MR)$$T 和 11$$_{K，是SiO 2}上石墨烯的三倍。基于标准二流体模型和LDA$+$U 模拟，我们表明观察到的增强的 MR 效应是由于通过石墨烯的 C 原子在 Fe ₃ O ₄的电荷有序 B 位阳离子上的排列通过电荷极化引起的石墨烯中的无序增加。我们的结果证明了一种通过将石墨烯与具有电荷轨道排序的合适基板耦合来增强石墨烯 MR 效应的潜在方法。