Patterning-Induced Ferromagnetism of Fe3GeTe2 van der Waals Materials beyond Room Temperature

Qian Li; Mengmeng Yang; Cheng Gong; Rajesh V Chopdekar; Alpha T N'Diaye; John Turner; Gong Chen; Andreas Scholl; Padraic Shafer; Elke Arenholz; Andreas K Schmid; Sheng Wang; Kai Liu; Nan Gao; Alemayehu S Admasu; Sang-Wook Cheong; Chanyong Hwang; Jia Li; Feng Wang; Xiang Zhang; Ziqiang Qiu

doi:10.1021/acs.nanolett.8b02806

Patterning-Induced Ferromagnetism of Fe₃GeTe₂ van der Waals Materials beyond Room Temperature

Nano Lett. 2018 Sep 12;18(9):5974-5980. doi: 10.1021/acs.nanolett.8b02806. Epub 2018 Aug 21.

Authors

Qian Li¹, Mengmeng Yang¹, Cheng Gong², Rajesh V Chopdekar, Alpha T N'Diaye, John Turner, Gong Chen³, Andreas Scholl, Padraic Shafer, Elke Arenholz, Andreas K Schmid, Sheng Wang¹, Kai Liu^{3

4}, Nan Gao¹, Alemayehu S Admasu⁵, Sang-Wook Cheong⁵, Chanyong Hwang⁶, Jia Li⁷, Feng Wang¹, Xiang Zhang², Ziqiang Qiu¹

Affiliations

¹ Department of Physics , University of California , Berkeley , California 94720 , United States.
² Nano-Scale Science and Engineering Center (NSEC) , University of California , 3112 Etcheverry Hall , Berkeley , California 94720 , United States.
³ Department of Physics , University of California , Davis , California 95616 , United States.
⁴ Department of Physics , Georgetown University , Washington , D.C. 20057 , United States.
⁵ Rutgers Center for Emergent Materials and Department of Physics and Astronomy , Rutgers, The State University of New Jersey , Piscataway , New Jersey 08854 , United States.
⁶ Korea Research Institute of Standards and Science , Yuseong, Daejeon 305-340 , Republic of Korea.
⁷ International Center for Quantum Materials, School of Physics , Peking University , Beijing 100871 , China.

PMID: 30114354
DOI: 10.1021/acs.nanolett.8b02806

Abstract

Magnetic van der Waals (vdW) materials have emerged as promising candidates for spintronics applications, especially after the recent discovery of intrinsic ferromagnetism in monolayer vdW materials. There has been a critical need for tunable ferromagnetic vdW materials beyond room temperature. Here, we report a real-space imaging study of itinerant ferromagnet Fe₃GeTe₂ and the enhancement of its Curie temperature well above ambient temperature. We find that the magnetic long-range order in Fe₃GeTe₂ is characterized by an unconventional out-of-plane stripe-domain phase. In Fe₃GeTe₂ microstructures patterned by a focused ion beam, the out-of-plane stripe domain phase undergoes a surprising transition at 230 K to an in-plane vortex phase that persists beyond room temperature. The discovery of tunable ferromagnetism in Fe₃GeTe₂ materials opens up vast opportunities for utilizing vdW magnets in room-temperature spintronics devices.

Keywords: Magnetic van der Waals material; room-temperature ferromagnetism; spin-reorientation transition; stripe-domain phase; vortex phase.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't