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Title: Magnetic Tunnel Junctions Based on CrO 2/SnO 2 Epitaxial Bilayers

Abstract

Magnetic tunnel junctions (MTJs) were fabricated using thin films of the half-metallic ferromagnet CrO2, employing semiconducting SnO2 tunnel barriers. Heteroepitaxial CrO2/SnO2 bilayers were grown on (100)-TiO2 substrates via chemical vapor deposition under atmospheric conditions. X-ray diffraction and transmission electron microscopy were used to confirm heteroepitaxy. A polycrystalline cobalt film forms the top magnetic electrode, yielding CrO2(001)/SnO2(001)/Co structures after patterning. Tunneling magnetoresistances (TMR) up to +14% at 5 K were observed. The sign of the TMR reverses for barrier thicknesses < 1nm, attributed to tunneling being dominated by Co-3d states at low thicknesses, and Co-4s states at larger thicknesses.

Authors:
 [1];  [1];  [1];  [2];  [2]
  1. University of Alabama, Tuscaloosa
  2. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1003563
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 89; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHEMICAL VAPOR DEPOSITION; COBALT; SUBSTRATES; THIN FILMS; TRANSMISSION ELECTRON MICROSCOPY; TUNNELING; X-RAY DIFFRACTION

Citation Formats

Miao, G. X., LeClair, P., Gupta, A., Varela del Arco, Maria, and Pennycook, Stephen J. Magnetic Tunnel Junctions Based on CrO2/SnO2 Epitaxial Bilayers. United States: N. p., 2006. Web. doi:10.1063/1.2216109.
Miao, G. X., LeClair, P., Gupta, A., Varela del Arco, Maria, & Pennycook, Stephen J. Magnetic Tunnel Junctions Based on CrO2/SnO2 Epitaxial Bilayers. United States. doi:10.1063/1.2216109.
Miao, G. X., LeClair, P., Gupta, A., Varela del Arco, Maria, and Pennycook, Stephen J. Sun . "Magnetic Tunnel Junctions Based on CrO2/SnO2 Epitaxial Bilayers". United States. doi:10.1063/1.2216109.
@article{osti_1003563,
title = {Magnetic Tunnel Junctions Based on CrO2/SnO2 Epitaxial Bilayers},
author = {Miao, G. X. and LeClair, P. and Gupta, A. and Varela del Arco, Maria and Pennycook, Stephen J},
abstractNote = {Magnetic tunnel junctions (MTJs) were fabricated using thin films of the half-metallic ferromagnet CrO2, employing semiconducting SnO2 tunnel barriers. Heteroepitaxial CrO2/SnO2 bilayers were grown on (100)-TiO2 substrates via chemical vapor deposition under atmospheric conditions. X-ray diffraction and transmission electron microscopy were used to confirm heteroepitaxy. A polycrystalline cobalt film forms the top magnetic electrode, yielding CrO2(001)/SnO2(001)/Co structures after patterning. Tunneling magnetoresistances (TMR) up to +14% at 5 K were observed. The sign of the TMR reverses for barrier thicknesses < 1nm, attributed to tunneling being dominated by Co-3d states at low thicknesses, and Co-4s states at larger thicknesses.},
doi = {10.1063/1.2216109},
journal = {Applied Physics Letters},
number = 2,
volume = 89,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}