Magnetoplumbite and W-type barium ferrites as magnetic mixture with hematite

Masubuchi, Yuji; Saito, Rui; Kikkawa, Shinichi

doi:10.2109/jcersj2.117.82

Cited by 2 publications

(1 citation statement)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed values were relatively small compared with the theoretical value of 31% expected from the spin polarization reported previously 15,16 . Recently, we have observed an MR effect in a sintered composite of hexagonal ferrox planar‐type barium ferrite and α‐Fe 2 O 3 17 that showed an MR ratio of 0.86% at room temperature. Both the lower resistivity of composite and the higher magnetization of FM grains were important factors contributing to the MR effect.…”

Section: Introductioncontrasting

confidence: 54%

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

Masubuchi

Minoya

Takeda

et al. 2010

Journal of the American Ceramic Society

Self Cite

View full text Add to dashboard Cite

The magnetoresistance (MR) of polycrystalline composites of ferromagnetic (FM) (M,Fe) 3 O 4 (M 5 Mn, Co, Ni, and Zn) spinel ferrite and weak FM a-Fe 2 O 3 insulator with spin canting was investigated. Sample disks were prepared by conventional solid-state sintering of a-Fe 2 O 3 , with either Mn 2 O 3 , Co 3 O 4 , NiO, or ZnO in a mixing ratio of M/Fe 5 x/(3Àx) 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) 3 O 4 /a-Fe 2 O 3 composite (x 5 0.25) sintered under air. The temperature dependence of the electrical resistivity showed a ln(q)pT À1/2 relationship, which suggests tunneling electron conduction in the granular composite. The MR ratio changed with the magnetization of the (M,Fe) 3 O 4 spinel ferrite, with a maximum at 2.02% where the (Mn,Fe) 3 O 4 ferrite grains were separated with the a-Fe 2 O 3 barrier of several micrometer thickness. The MR may be attributed to spin polarization in the ferrite grains coupled with the a-Fe 2 O 3 insulating barrier, where its spins are slightly canting in strong anti-FM interaction. P. A. Joy-contributing editor *Member, The American Ceramic Society.

show abstract

Section: Introductioncontrasting

confidence: 54%

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

Masubuchi

Minoya

Takeda

et al. 2010

Journal of the American Ceramic Society

Self Cite

View full text Add to dashboard Cite

show abstract

Effects of Ca2+-Doping on the Crystal Lattice of α-Fe2O3

Andrade

Passos

Macêdo

2014

AMR

View full text Add to dashboard Cite

Samples of CayFe12-yO19 (0 ≤ y ≤ 1.0) were prepared by a proteic sol–gel process with hematite phase and clusters of M-type calcium hexaferrite. Impedance analysis showed that the resistivity increased with calcium concentration in the 0.0 < y ≤ 0.2 range, but decreased for y > 0.2. The saturation of the electrical resistivity occurred at 7.5 × 106 Ω·cm for Ca0.9Fe11.1O19. The plot of magnetization as a function of the magnetic field showed high values of saturation magnetization (40 emu/g) with low remanence (6.7 emu/g) and coercive field (320 Oe).

show abstract

Magnetoplumbite and W-type barium ferrites as magnetic mixture with hematite

Cited by 2 publications

References 19 publications

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

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

Effects of Ca<sup>2+</sup>-Doping on the Crystal Lattice of α-Fe<sub>2</sub>O<sub>3</sub>

Contact Info

Product

Resources

About