Inelastic magnon and phonon excitations in Al1-xCox/Al1-xCox-oxide/Al tunnel junctions

Xiu Feng Han, Junichirou Murai, Yasuo Ando, Hitoshi Kubota, Terunobu Miyazaki

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23 Citations (Scopus)


Magnetoelectric properties of the tunnel junctions, Al(50 nm)/Al2O3(1.2 nm)/Al(50 nm) (x = 0), Al(55 nm)/Al2O3(1.0 nm)/Co(55 nm) (x=0 and top electrode is Co), and Al1-xCox(55 nm)/Al1-xCox-oxide(d nm)/Al(55 nm) (x=0.25, 0.50, 0.75, and 1.0), were investigated. Oxides of Al1-xCox (x=0, 0.25, 0.50, 0.75, and 1.0) were chosen as barrier materials in order to modulate the magnon and phonon excitations in the barrier layer and the interfaces. It was shown that the magnon and phonon excitations were the main sources of inelastic scattering in the tunneling processes for the conduction electrons in these tunnel junctions at nonzero bias voltages. The magnon effects were enhanced in the Co-rich barrier junctions. The Al-O-Co phonon energy decreased with increasing Co composition between the Al-O and Co-O phonon energies based on an Al-O-Co stretching mode in the Al1-xCox-oxide barrier as vibrational frequency of crystal lattice decreased with increasing Co composition.

Original languageEnglish
Pages (from-to)2533-2535
Number of pages3
JournalApplied Physics Letters
Issue number17
Publication statusPublished - 2001 Apr 23


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