Skip to main content

Electron Transport Under Magnetic Field in Insulating Hematite Composites with Spinel Ferrite

Buy Article:

$51.00 plus tax (Refund Policy)


The magnetoresistance (MR) of polycrystalline composites of ferromagnetic (FM) (M,Fe)3O4 (M=Mn, Co, Ni, and Zn) spinel ferrite and weak FM α-Fe2O3 insulator with spin canting was investigated. Sample disks were prepared by conventional solid-state sintering of α-Fe2O3, with either Mn2O3, Co3O4, NiO, or ZnO in a mixing ratio of M/Fe=x/(3−x) at 1473 K for 10 h under Ar or air atmospheres. The largest MR ratios of 2.02% at room temperature and 11.7% at 77 K were observed under a magnetic field of 0.5 T for the (Mn,Fe)3O4/α-Fe2O3 composite (x=0.25) sintered under air. The temperature dependence of the electrical resistivity showed a ln()∝T−1/2 relationship, which suggests tunneling electron conduction in the granular composite. The MR ratio changed with the magnetization of the (M,Fe)3O4 spinel ferrite, with a maximum at 2.02% where the (Mn,Fe)3O4 ferrite grains were separated with the α-Fe2O3 barrier of several micrometer thickness. The MR may be attributed to spin polarization in the ferrite grains coupled with the α-Fe2O3 insulating barrier, where its spins are slightly canting in strong anti-FM interaction.

Document Type: Research Article


Affiliations: Graduate School of Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo 060-8628, Japan

Publication date: March 1, 2011


Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more