Double-Exchange Effect in Two-Dimensional MnO2 Nanomaterials

Xu Peng; Yuqiao Guo; Qin Yin; Junchi Wu; Jiyin Zhao; Chengming Wang; Shi Tao; Wangsheng Chu; Changzheng Wu; Yi Xie

doi:10.1021/jacs.7b01903

Double-Exchange Effect in Two-Dimensional MnO₂ Nanomaterials

J Am Chem Soc. 2017 Apr 12;139(14):5242-5248. doi: 10.1021/jacs.7b01903. Epub 2017 Mar 29.

Authors

Xu Peng¹, Yuqiao Guo¹, Qin Yin¹, Junchi Wu¹, Jiyin Zhao¹, Chengming Wang¹, Shi Tao², Wangsheng Chu², Changzheng Wu¹, Yi Xie¹

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), CAS Center for Excellence in Nanoscience, and CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China , Hefei, Anhui 230026, P. R. China.
² National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei, Anhui 230029, P. R. China.

PMID: 28306253
DOI: 10.1021/jacs.7b01903

Abstract

Electronic state transitions, especially metal-insulator transitions (MIT), offer physical properties that are useful in intriguing energy applications and smart devices. But to-date, very few simple metal oxides have been shown to undergo electronic state transitions near room temperature. Herein, we demonstrate experimentally that chemical induction of double-exchange in two-dimensional (2D) nanomaterials brings about a MIT near room temperature. In this case, valence-state regulation of a 2D MnO₂ nanosheet induces a Mn(III)-O-Mn(IV) structure with the double-exchange effect, successfully triggering a near-room-temperature electronic transition with an ultrahigh negative magneto-resistance (MR). Double-exchange in 2D MnO₂ nanomaterials exhibits an ultrahigh MR value of up to -11.3% (0.1 T) at 287 K, representing the highest reported negative MR values in 2D nanomaterials approaching room temperature. Also, the MnO₂ nanosheet displays an infrared response of 7.1% transmittance change on going from 270 to 290 K. We anticipate that dimensional confinement of double-exchange structure promises novel magneto-transport properties and sensitive responses for smart devices.