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Title: X-ray absorption spectroscopy studies on magnetic tunnel junctions with AlO and AlN tunnel barriers

Abstract

X-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) measurements of the optimized magnetic tunnel junctions (MTJs) with AlO and AlN barriers have been performed to study the chemical structures of the barrier and the underlying layer. These MTJs with AlO and AlN barriers exhibited increased tunneling magnetoresistance (TMR) after annealing at 200 deg. C from 27% to 45% and from 25% to 33%, respectively. Surprisingly, the XPS and XAS measurements confirmed that both the as-grown and the annealed MTJs had metallic Co and Fe at the interface between the barrier and the underlying CoFe layer. After annealing, under-stoichiometric AlO{sub x} and AlN{sub x} phases in MTJs with AlO and AlN barriers partially transformed into stoichiometric Al{sub 2}O{sub 3} and AlN phases, respectively. Thus the increase in TMR after annealing for MTJs with clean interface between the barrier and the underlying layer is believed due to the anion redistribution inside the barrier layer, not from back diffusion from pinned magnetic layer to barrier layer.

Authors:
; ; ; ; ; ;  [1];  [2];  [2];  [2]
  1. Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
  2. (Korea, Republic of)
Publication Date:
OSTI Identifier:
20788121
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 8; Conference: 50. annual conference on magnetism and magnetic materials, San Jose, CA (United States), 30 Oct - 3 Nov 2005; Other Information: DOI: 10.1063/1.2176055; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION SPECTROSCOPY; ALUMINIUM NITRIDES; ALUMINIUM OXIDES; ANIONS; ANNEALING; COBALT ALLOYS; INTERFACES; IRON ALLOYS; LAYERS; MAGNETORESISTANCE; STOICHIOMETRY; SUPERCONDUCTING JUNCTIONS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0400-1000 K; TUNNEL EFFECT; X-RAY PHOTOELECTRON SPECTROSCOPY; X-RAY SPECTRA; X-RAY SPECTROSCOPY

Citation Formats

Mun, B. S., Moon, J. C., Hong, S. W., Kang, K. S., Kim, K., Kim, T. W., Ju, H. L., Department of Physics, Yonsei University, Seoul 120-749, Devices Laboratory, Samsung Advanced Institute of Technology, Giheung, Kyunggi-do 449-711, and Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 and Department of Physics, Yonsei University, Seoul 120-749. X-ray absorption spectroscopy studies on magnetic tunnel junctions with AlO and AlN tunnel barriers. United States: N. p., 2006. Web. doi:10.1063/1.2176055.
Mun, B. S., Moon, J. C., Hong, S. W., Kang, K. S., Kim, K., Kim, T. W., Ju, H. L., Department of Physics, Yonsei University, Seoul 120-749, Devices Laboratory, Samsung Advanced Institute of Technology, Giheung, Kyunggi-do 449-711, & Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 and Department of Physics, Yonsei University, Seoul 120-749. X-ray absorption spectroscopy studies on magnetic tunnel junctions with AlO and AlN tunnel barriers. United States. doi:10.1063/1.2176055.
Mun, B. S., Moon, J. C., Hong, S. W., Kang, K. S., Kim, K., Kim, T. W., Ju, H. L., Department of Physics, Yonsei University, Seoul 120-749, Devices Laboratory, Samsung Advanced Institute of Technology, Giheung, Kyunggi-do 449-711, and Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 and Department of Physics, Yonsei University, Seoul 120-749. Sat . "X-ray absorption spectroscopy studies on magnetic tunnel junctions with AlO and AlN tunnel barriers". United States. doi:10.1063/1.2176055.
@article{osti_20788121,
title = {X-ray absorption spectroscopy studies on magnetic tunnel junctions with AlO and AlN tunnel barriers},
author = {Mun, B. S. and Moon, J. C. and Hong, S. W. and Kang, K. S. and Kim, K. and Kim, T. W. and Ju, H. L. and Department of Physics, Yonsei University, Seoul 120-749 and Devices Laboratory, Samsung Advanced Institute of Technology, Giheung, Kyunggi-do 449-711 and Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 and Department of Physics, Yonsei University, Seoul 120-749},
abstractNote = {X-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) measurements of the optimized magnetic tunnel junctions (MTJs) with AlO and AlN barriers have been performed to study the chemical structures of the barrier and the underlying layer. These MTJs with AlO and AlN barriers exhibited increased tunneling magnetoresistance (TMR) after annealing at 200 deg. C from 27% to 45% and from 25% to 33%, respectively. Surprisingly, the XPS and XAS measurements confirmed that both the as-grown and the annealed MTJs had metallic Co and Fe at the interface between the barrier and the underlying CoFe layer. After annealing, under-stoichiometric AlO{sub x} and AlN{sub x} phases in MTJs with AlO and AlN barriers partially transformed into stoichiometric Al{sub 2}O{sub 3} and AlN phases, respectively. Thus the increase in TMR after annealing for MTJs with clean interface between the barrier and the underlying layer is believed due to the anion redistribution inside the barrier layer, not from back diffusion from pinned magnetic layer to barrier layer.},
doi = {10.1063/1.2176055},
journal = {Journal of Applied Physics},
number = 8,
volume = 99,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}