Boron migration due to annealing in CoFeB/MgO/CoFeB interfaces: A combined hard x-ray photoelectron spectroscopy and x-ray absorption studies

Journal Article · Mon Nov 28 04:00:00 EST 2011 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3662967· OSTI ID:1043378

K, Rumaiz A; Jaye, C; Woicik, J C

We report the hard x-ray photo-electron spectroscopy (HAXPES) and near edge x-ray absorption fine structure (NEXAFS) of CoFeB|MgO|CoFeB interfaces as a function of annealing time. Upon annealing, the oxidation state of B changes from predominantly elemental (0 valence) boron in the as deposited sample to higher oxidation in annealed samples as evident from HAXPES spectra. The NEXAFS spectroscopy results showed that upon heating, B species migrate towards the MgO and interact with it. A comparison of the tunnel junction NEXAFS signature with some standards suggests that the B forms a 3-fold coordinated boron compound in the MgO environment and 4-fold coordinated boron resembling Kotoite mineral in the CoFe/MgO interface.

• Research Organization: BROOKHAVEN NATIONAL LABORATORY (BNL)
• Sponsoring Organization: USDOE SC OFFICE OF SCIENCE (SC)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1043378
• Report Number(s): BNL--96904-2012-JA
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 22 Vol. 99; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTROSCOPY
ANNEALING
BORON
BORON COMPOUNDS
COBALT COMPOUNDS
FINE STRUCTURE
HEATING
IRON COMPOUNDS
MAGNESIUM COMPOUNDS
OXIDATION
SPECTRA
VALENCE
X-RAY PHOTOELECTRON SPECTROSCOPY