Room-Temperature Ferromagnetism and Extraordinary Hall Effect in Nanostructured Q-Carbon: Implications for Potential Spintronic Devices

2018 ◽  
Vol 1 (2) ◽  
pp. 807-819 ◽  
Author(s):  
Anagh Bhaumik ◽  
Sudhakar Nori ◽  
Ritesh Sachan ◽  
Siddharth Gupta ◽  
Dhananjay Kumar ◽  
...  
2011 ◽  
Vol 50 (5) ◽  
pp. 05FB02 ◽  
Author(s):  
Naotaka Uchitomi ◽  
Hiroto Oomae ◽  
Joel T. Asubar ◽  
Hironori Endo ◽  
Yoshio Jinbo

2011 ◽  
Vol 84 (7) ◽  
Author(s):  
B. A. Aronzon ◽  
V. V. Rylkov ◽  
S. N. Nikolaev ◽  
V. V. Tugushev ◽  
S. Caprara ◽  
...  

2006 ◽  
Vol 16 (02) ◽  
pp. 515-543
Author(s):  
MATTHEW H. KANE ◽  
MARTIN STRASSBURG ◽  
WILLIAM E. FENWICK ◽  
ALI ASGHAR ◽  
IAN T. FERGUSON

Wide-bandgap dilute magnetic semiconductors (DMS), such as transition-metal doped ZnO and GaN , have gained attention for use in spintronic devices because of predictions and experimental reports of room temperature ferromagnetism which may enable their use in spintronic devices. However, there has been some debate over the source of ferromagnetism in these materials. This paper focuses on the high quality growth of wide bandgap DMS, and the characterization of Zn 1-x Mn x O produced by melt-growth techniques and Ga 1-x Mn x N grown by metal organic chemical vapor deposition (MOCVD). High resolution X-ray diffraction results revealed no second phases in either the ZnO crystals or the GaN films. Undoped as-grown, bulk crystals of Zn 1-x Mn x O and Zn 1-x Co x O crystals are shown to be paramagnetic at all temperatures. In contrast, the Ga 1-x Mn x N films showed ferromagnetic behavior at room temperature under optimum growth conditions. Experimental identification of the Mn ion charge state and the presence of bands in the bandgap of GaN are investigated by optical spectroscopy and electron spin paramagnetic resonance (EPR). It is shown that the broadening of states in the Mn 3d shell scaled with Mn concentration, and that optical transitions due to this band correlated with the strong ferromagnetism in these samples. However, this band disappeared with an increase in free electron concentration provided by either annealing or doping. Raman studies of Ga 1-x Mn x N revealed two predominant Mn -related modes featured with increasing concentration, a broad disorder related structure at 300cm-1 and a sharper peak at 669cm-1 This works show that the development of practical ferromagnetic wide bandgap DMS materials for spintronic applications will require both the lattice site introduction of Mn as well as careful control of the background defect concentration to optimize these materials.


Author(s):  
Weizhen Meng ◽  
Xiaoming Zhang ◽  
Ying Liu ◽  
Xuefang Dai ◽  
HongLi Gao ◽  
...  

Electrides in two-dimensional (2D) scale, especially those capture inherent magnetism and low work functions, have shown great application prospects in nanoscale spintronic devices and electronic emitters. However, searching ideal 2D...


Author(s):  
Guang Song ◽  
Chengfeng Zhang ◽  
Zhengzhong Zhang ◽  
Guannan Li ◽  
Zhongwen Li ◽  
...  

Two-dimensional (2D) materials with intrinsic ferromagnetism and piezoelectricity have received growing attention due to their potential applications in nanoscale spintronic devices. However, their applications are highly limited by the low...


2007 ◽  
Vol 1032 ◽  
Author(s):  
N. Mamidi ◽  
R. K. Gupta ◽  
K. Ghosh ◽  
S. R. Mishra ◽  
P. K. Kahol

AbstractRecently, oxide-based dilute magnetic semiconductors (DMS) have attracted an immense research interest to the scientists due to the possibility of inducing room temperature ferromagnetism and potential uses in novel spintronic devices. In2O3, a transparent opto-electronic material, is an interesting prospect for spintronics due to its unique combination of magnetic, electrical, and optical properties. High quality thin films of Co-doped In2O3 DMS were grown on quartz substrates using pulsed laser deposition technique. All the films have been characterized using different techniques such as x-ray diffraction, Raman spectroscopy, optical transmission spectroscopy, electrical resistivity, and Hall Effect measurement. The effect of growth temperature and oxygen pressure on the electrical, magnetic, and optical properties of these films have been studied in detail. The optical transparency in all the films is high. It has been observed that the optical transparency depends on growth temperature and oxygen pressure. The electrical parameters such as resistivity, carrier concentration, and mobility strongly depend on both oxygen pressure and growth temperature. The films grown at low temperature are semiconducting in nature while the films grown at high temperature are metallic. Detailed temperature and magnetic field dependent resistivity, magnetoresistance, and Hall effect data will be presented. This work is supported by Research Corporation (award number CC6166).


2020 ◽  
Vol 6 (3) ◽  
pp. eaay8912 ◽  
Author(s):  
Junho Seo ◽  
Duck Young Kim ◽  
Eun Su An ◽  
Kyoo Kim ◽  
Gi-Yeop Kim ◽  
...  

In spintronics, two-dimensional van der Waals crystals constitute a most promising material class for long-distance spin transport or effective spin manipulation at room temperature. To realize all-vdW-material–based spintronic devices, however, vdW materials with itinerant ferromagnetism at room temperature are needed for spin current generation and thereby serve as an effective spin source. We report theoretical design and experimental realization of a iron-based vdW material, Fe4GeTe2, showing a nearly room temperature ferromagnetic order, together with a large magnetization and high conductivity. These properties are well retained even in cleaved crystals down to seven layers, with notable improvement in perpendicular magnetic anisotropy. Our findings highlight Fe4GeTe2 and its nanometer-thick crystals as a promising candidate for spin source operation at nearly room temperature and hold promise to further increase Tc in vdW ferromagnets by theory-guided material discovery.


2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Thomas Tietze ◽  
Patrick Audehm ◽  
Yu–Chun Chen ◽  
Gisela Schütz ◽  
Boris B. Straumal ◽  
...  

Abstract Diamagnetic oxides can, under certain conditions, become ferromagnetic at room temperature and therefore are promising candidates for future material in spintronic devices. Contrary to early predictions, doping ZnO with uniformly distributed magnetic ions is not essential to obtain ferromagnetic samples. Instead, the nanostructure seems to play the key role, as room temperature ferromagnetism was also found in nanograined, undoped ZnO. However, the origin of room temperature ferromagnetism in primarily non–magnetic oxides like ZnO is still unexplained and a controversial subject within the scientific community. Using low energy muon spin relaxation in combination with SQUID and TEM techniques, we demonstrate that the magnetic volume fraction is strongly related to the sample volume fraction occupied by grain boundaries. With molecular dynamics and density functional theory we find ferromagnetic coupled electron states in ZnO grain boundaries. Our results provide evidence and a microscopic model for room temperature ferromagnetism in oxides.


2006 ◽  
Vol 959 ◽  
Author(s):  
Shalini Gupta ◽  
Hun Kang ◽  
Matthew H. Kane ◽  
Eun Hyun Park ◽  
Ian T. Ferguson

ABSTRACTThe growth of Ga1-xMnxN and Ga1-xFexN nanostructures was carried out by MOCVD. Introduction of transition metals (TM) Mn and Fe in GaN nanostructures enhanced the nucleation of the nanostructures resulting in reduced lateral dimensions and increased nanostructure density. The Ga1-xMnxN nanostructures showed hysteresis behavior at 5K. Room temperature ferromagnetism was obtained in the Ga1-xFexN nanostructures unlike its bulk counterpart. This paper presents the growth and magnetization study of Ga1-xTMxN nanostructures. These structures could be used to enhance the efficiency of spintronic devices.


Sign in / Sign up

Export Citation Format

Share Document