Magnetic Tunnel Junctions Based on CrO₂/SnO₂ Epitaxial Bilayers

Journal Article · Sun Jan 01 00:00:00 EST 2006 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2216109· OSTI ID:1003563

Miao, G. X. ^[1]; LeClair, P. ^[1]; Gupta, A. ^[1]; Varela del Arco, Maria ^[2]; Pennycook, Stephen J ^[2]

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1. University of Alabama, Tuscaloosa
2. ORNL

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.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1003563
• Journal Information: Applied Physics Letters, Vol. 89, Issue 2; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHEMICAL VAPOR DEPOSITION
COBALT
SUBSTRATES
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
TUNNELING
X-RAY DIFFRACTION