Research Article Thickness Dependent Interlayer Magnetoresistance in Multilayer Graphene Stacks S. C. Bodepudi, 1 X. Wang, 2 A. P. Singh, 1 and S. Pramanik 1 1 Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB, Canada T6G 2V4 2 School of Microelectronics and Solid State Electronics, UESTC, Chengdu, Sichuan 610054, China Correspondence should be addressed to S. Pramanik; spramani@ualberta.ca Received 21 February 2016; Accepted 21 June 2016 Academic Editor: Rakesh Joshi Copyright © 2016 S. C. Bodepudi et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Chemical Vapor Deposition grown multilayer graphene (MLG) exhibits large out-of-plane magnetoresistance due to interlayer magnetoresistance (ILMR) efect. It is essential to identify the factors that infuence this efect in order to explore its potential in magnetic sensing and data storage applications. It has been demonstrated before that the ILMR efect is sensitive to the interlayer coupling and the orientation of the magnetic feld with respect to the out-of-plane (-axis) direction. In this work, we investigate the role of MLG thickness on ILMR efect. Our results show that the magnitude of ILMR efect increases with the number of graphene layers in the MLG stack. Surprisingly, thicker devices exhibit feld induced resistance switching by a factor of at least ∼10 7 . Tis efect persists even at room temperature and to our knowledge such large magnetoresistance values have not been reported before in the literature at comparable felds and temperatures. In addition, an oscillatory MR efect is observed at higher feld values. A physical explanation of this efect is presented, which is consistent with our experimental scenario. Graphene, a single atomic layer of hexagonally arranged carbon atoms, is one of the most investigated material systems in recent years. Charge carriers in graphene behave like two- dimensional (2D) Dirac fermions and exhibit various novel phenomena that are generally not observed in conventional materials [1–4]. It is interesting to note that many of the efects that are observed in monolayer graphene have also been reported in multilayer graphene (MLG) [5–9]. For some of the applications, multilayer graphene can be a better alternative due to its robustness and simpler fabrication steps [8–11]. In recent years, much attention has been given to multilayer graphene structures for next generation sensor and data storage applications [8, 12–19]. In particular, var- ious magnetoresistance (MR) efects have been extensively explored in multilayer graphene due to their potential to exist even at room temperature [14, 18–20]. However, many of these efects are signifcant at very large magnetic felds (∼100 kG) that are outside the range generally required for practical applications [21, 22]. We recently demonstrated a large negative MR in multilayer graphene at low-feld range (∼2 kG) [16, 17], which ofen persists even at room temperature. Te origin of this large negative MR is related to the existence of 2D Dirac fermions in multilayer graphene. In general, the linear energy dispersion of monolayer graphene no longer exists in MLG (or, graphite) due to strong interlayer coupling between neighboring graphene layers [4, 23, 24]. However, in case of “turbostratic” MLG, in which graphene layers are randomly oriented, interlayer coupling is weakened and the massless Dirac fermion nature of each graphene layer is preserved [25, 26]. Such turbostratic MLG can be realized by chemical vapor deposition (CVD) process using polycrystalline Ni as a catalyst [27, 28]. We demonstrated previously [16, 17] that such a weakly coupled MLG stack exhibits a unique quantum mechanical MR efect, known as interlayer magnetoresistance (ILMR). To further understand and explore potential applications based on ILMR efect, it is important to identify the factors that infuence this efect. In our present study we report efect of MLG thickness on ILMR. Tickness of the MLG stack can be varied by the CVD growth parameters. To our knowledge, such thickness dependent ILMR studies have never been performed in any multilayer Dirac carrier system. Hindawi Publishing Corporation Journal of Nanomaterials Volume 2016, Article ID 8163742, 10 pages http://dx.doi.org/10.1155/2016/8163742