Details

Autor(en) / Beteiligte

• Kohiki, Shigemi
• Kinoshita, Tomoki
• Nara, Koichiro
• Akiyama-Hasegawa, Kotone
• Mitome, Masanori

Titel

Large, negative magnetoresistance in an oleic acid-coated Fe(3)O(4) nanocrystal self-assembled film

Ist Teil von

• ACS applied materials & interfaces, 2013-11, Vol.5 (22), p.11584-11589

Ort / Verlag

United States

Erscheinungsjahr

2013

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• An oleic acid-coated Fe3O4 nanocrystal self-assembled film was fabricated via drop casting of colloidal particles on a SiO2/Si substrate. The film exhibited bifurcation of the zero-field-cooled and field-cooled magnetizations around 250 K. The nonlinear current-voltage (I-V) characteristics between the source and drain electrodes in both zero and non-zero magnetic fields (H) were observed above and below the bifurcation temperature. A large negative magnetoresistance (MR ≈ -60%) was achieved at 200 K and H = 1 T. Even at 295 K and 0.2 T, the negative MR (∼ -50%) persisted. A Fowler-Nordheim plot and power-law scaling of the I-V characteristics revealed that the current flows through two-dimensional (2D) percolated electron tunneling paths. The enlargement of MR can be attributed to spin-dependent electron tunneling between magnetically coupled Fe3O4 nanocrystals self-assembled in 2D ordered arrays.