Large grain-boundary magnetoresistance in MnFe2O4 nanoparticle compact

Wang, Junfeng; Deng, Hong; Li, Yadong; Song, Pengyun; Shi, Jing

doi:10.1016/j.jmmm.2007.05.023

Cited by 9 publications

(7 citation statements)

References 19 publications

(44 reference statements)

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“…The smaller MR ratios in the present products may be due to the difference in the electron conduction mechanism from that for the Zn 0.41 Fe 2.59 O 4 /α‐Fe 2 O 3 composite. The largest MR ratio of 2.02% obtained in the present (Mn,Fe) 3 O 4 /α‐Fe 2 O 3 composite was again smaller than the MR ratio of 6% reported for a MnFe 2 O 4 nanoparticle compact at 300 K 20 . The very thick α‐Fe 2 O 3 barrier layer may contribute to the smaller MR ratio in the present (Mn,Fe) 3 O 4 /α‐Fe 2 O 3 composite as discussed in the next section.…”

Section: Resultscontrasting

confidence: 77%

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

Masubuchi

Minoya

Takeda

et al. 2010

Journal of the American Ceramic Society

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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.

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Section: Resultscontrasting

confidence: 77%

“…An exceptionally large MR ratio of approximately 61% has been reported for a polycrystalline hematite composite with spinel Zn 0.41 Fe 2.59 O 4 ferrite, which has a relatively small magnetic moment among the spinel ferrites 19 . Wang et al 20 . reported an MR ratio of 6% for a single‐phase MnFe 2 O 4 nanoparticle compact.…”

Section: Introductionmentioning

confidence: 99%

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

Masubuchi

Minoya

Takeda

et al. 2010

Journal of the American Ceramic Society

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“…[9][10][11][12][13][14] The magnetoresistive response has been found in some ferrite systems, which makes them more interesting for technological applications. 9,15 Therefore, in order to understand magnetoresistive phenomena, it is interesting to study the origin of the electrical resistance behavior during electrical transitions, and its effect on the magnetoresistance coefficient. In the present work, manganese and zinc ferrites were obtained by mechanical milling.…”

Section: Introductionmentioning

confidence: 99%

Magneto-resistive coefficient enhancement observed around Verwey-like transition on spinel ferrites XFe2O4 (X = Mn, Zn)

Maldonado

Zubiate

Presa

et al. 2014

Journal of Applied Physics

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Manganese and Zinc ferrites were prepared by solid state reaction. The resulting powders were pressed into pellets and heat treated at 1100 C. The samples were characterized by using X-ray diffraction, pure phases of zinc ferrite (ZnFe 2 O 4 ) and manganese ferrite (MnFe 2 O 4 ) were obtained. Scanning electron microscopy images showed a good contact between particles. A drop of electrical resistance was found in both samples, MnFe 2 O 4 and ZnFe 2 O 4 , with values going from 2750 to 130 X and from 1100 to 55 X, respectively. Transition temperatures were determined to be T V ¼ 225 K for MnFe 2 O 4 and T V ¼ 130 K for ZnFe 2 O 4 . Magnetoresistance measurements were carried out in the temperature range where R showed the transition, defined as the Verwey-like transition temperature range, DT V . No magnetoresistive effect was observed out of it. The magnetoresistive coefficient (MRC) observed at DT V reached its maximum values of 1.1% for MnFe 2 O 4 and 6.68% for ZnFe 2 O 4 . The differences between MRC values are related to the divalent metal element used. Finally, the magnetoresistive response indicates that the electrical transition observed is strongly influencing the magnetoresistance; where the underlying responsible for this behavior could be a charge reordering occurring at the Verwey-like transition temperature. V C 2014 AIP Publishing LLC. [http://dx

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“…[7][8][9][10][11][12][13][14][15] Only a few reports are found for other spinel ferrites. [16][17][18] Unfortunately, however, the largest MR ratio ever reported for magnetite is only 1.2% in 1.5 kOe at RT. 7 Similarly, other spinel ferrites are reported to have low LFMR ratios.…”

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confidence: 97%

“…For instance, a MnFe 2 O 4 nanoparticle compact is reported to exhibit the LFMR ratio of ∼ 1% in 0.5 kOe at RT. 18 On the other hand, the MnZn ferrite must also be a potential candidate to overcome the present limitation of the LFMR ratio at RT since MnZn ferrites have relatively high saturation magnetization and low electrical resistivity in comparison with other spinel ferrites. 19 MnZn ferrites have been normally applied for high density magnetic cores, read-write heads for high speed disk recording, high-frequency transformers, and high-frequency inductors.…”

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confidence: 99%

Excellent low-field magnetoresistance effect in Ga-doped MnZn ferrites

Kim

Yoo

2014

AIP Advances

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An excellent low field magnetoresistance (LFMR) property was achieved from the Ga-doped (Mn0.8Zn0.2)Fe2O4 (MnZn) ferrites at room temperature (RT). For this study, undoped and Ga-doped MnZn ferrites with the nominal compositions of (Mn0.8Zn0.2)1−xGaxFe2O4 (x = 0 ∼ 0.1) were prepared by the conventional solid state reaction at 1400°C for 2 h in air. From the magneto-transport measurements, Ga-doped MnZn ferrites were found to have not only much lower resistivity values but also greatly improved LFMR ratios in comparison with undoped sample. The highest maximum LFMR ratio of 2.5% at 290 K in 0.5 kOe was achievable from 2 mol% Ga-doped MnZn ferrite. This large LFMR effect is attributable to an increase in spin electrons by Ga3+ ion substitution for the (Mn, Zn)2+ site.

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Large grain-boundary magnetoresistance in MnFe2O4 nanoparticle compact

Cited by 9 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

Magneto-resistive coefficient enhancement observed around Verwey-like transition on spinel ferrites XFe2O4 (X = Mn, Zn)

Excellent low-field magnetoresistance effect in Ga-doped MnZn ferrites

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