Superparamagnetic Reduced Graphene Oxide with Large Magnetoresistance: A Surface Modulation Strategy. Issue 9 (28th January 2016)

• Record Type: Journal Article
• Authors: Peng, Jing; Guo, Yuqiao; Lv, Haifeng; Dou, Xinyu; Chen, Qi; Zhao, Jiyin; Wu, Changzheng; Zhu, Xiaojiao; Lin, Yue; Lu, Wei; Wu, Xiaojun; Xie, Yi
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 9(2016)
• Page Start: 3176
• Page End: 3180
• Publication Date: 2016-01-28
• Subjects: magnetic properties -- magnetoresistance -- reduced graphene oxide -- superparamagnetism -- surface modulation; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201511436
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The graphene system is actively pursued in spintronics for its nontrivial sp electron magnetism and its potential for the flexible surface chemical tuning of magnetoelectronic functionality. The magnetoresistance (MR) of graphene can be effectively tuned under high magnetic fields at cryogenic temperatures, but it remains a challenge to achieve sensitive magnetoelectric response under ambient conditions. We report the use of surface modulation to realize superparamagnetism in reduced graphene oxide (rGO) with sensitive magnetic field response. The superparamagnetic rGO was obtained by a mild oxidation process to partially remove the thiol groups covalently bound to the carbon framework, which brings about large low‐field negative MR at room temperature (−8.6 %, 500 Oe, 300 K). This strategy provides a new approach for optimizing the intrinsic magnetoelectric properties of two‐dimensional materials. Abstract : Beneath the surface : Modification of graphene oxide with thiol groups results in ferromagnetic reduced graphene oxide; subsequent mild oxidation and partial thiol group removal produces superparamagnetic reduced graphene oxide. The magnetic domains are reduced to a critical size and the number of unpaired spins decreased to result in a superparamagnetic structure. This material shows large negative low‐field magnetoresistance at ambient temperature.