Influence of reducing thermo-chemical treatment on magnetic properties of magnetite Fe3O4 (100) epitaxial films

Yinqing, Zhou; McEvoy, Ciaran; Shvets, I. V.

doi:10.1016/j.jmmm.2004.11.364

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…With further irradiation the contrast is reduced. Recently, Zhou et al 20,30 have attempted to modify the APBs in Fe 3 O 4 thin films using thermo-chemical treatment, i.e., annealing the films at 250°C in air for different time duration, and have observed an increase in saturation magnetization, but at the same time they observed that the Verwey transition was decreased. In the present case, contrary to their results, the Verwey transition temperature and magnetization both increased with SHI irradiation up to an optimum value of ion fluence, which clearly indicates that SHI irradiation has modified the APB structure and possibly annealed out some of the APBs.…”

Section: Resultsmentioning

confidence: 99%

Swift heavy ion irradiation-induced modifications in structural, magnetic and electrical transport properties of epitaxial magnetite thin films

Kumar

Khan

Srivastava

et al. 2006

Journal of Applied Physics

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The effect of swift heavy ion ͑SHI͒ irradiation ͑190 MeV Ag͒ on structural, electrical transport and magnetic properties of epitaxial magnetite ͑Fe 3 O 4 ͒ thin films ͑thickness ϳ70 nm͒ grown on MgO͗100͘ oriented substrate have been investigated. The x-ray diffraction shows that at low fluence values up to 5 ϫ 10 11 ions/ cm 2 , the strain in the films is relaxed, whereas, at higher fluence range 1 ϫ 10 12 -1 ϫ 10 13 ions/ cm 2 , the epitaxial relationship with the substrate is lost along with a phase transformation from magnetite to more oxidized magnetite phase ͑i.e., maghemite͒. The Verwey transition temperature measured by electrical transport is found to increase from 109 to 117 K with the low fluence SHI irradiation, which is related to the irradiation induced strain relaxation and structural modifications. At higher fluences the system did not show Verwey transition and the resistance is also increased. The similar results were obtained by magnetization studies. The observed magnetization at 1 T field is increased at low fluence suggesting the reduction of areas with frustrated exchange interactions associated with the cationic arrangement at the anti phase boundaries. At higher fluences it decreases monotonically, indicating the emergence of other phases. The observed modifications are explained on the basis of structural strain and disorder induced by swift heavy ions, which lead to modification of the interionic Coulomb potential at octahedral sublattices and bandwidth in this system.

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Section: Resultsmentioning

confidence: 99%

Swift heavy ion irradiation-induced modifications in structural, magnetic and electrical transport properties of epitaxial magnetite thin films

Kumar

Khan

Srivastava

et al. 2006

Journal of Applied Physics

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“…6,11 Therefore, a change in the strain state does not appear to be responsible for the anomaly properties as all the films are equally strained. The dead layer formed by Mg diffusion between the MgO substrate and the magnetite films and also the dead layer on the top uncapped film are considered as the possible reasons for the anomalies in resistivity and magnetic properties of the ultrathin films.…”

Section: Resultsmentioning

confidence: 99%

The magnetic and magnetoresistance properties of ultrathin magnetite films grown on MgO substrate

Yinqing

McEvoy

Ramos

et al. 2006

Journal of Applied Physics

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We report on the properties of ultrathin ͑2, 4, 6, and 8 nm͒ epitaxial films of magnetite, Fe 3 O 4 , grown on MgO ͑100͒. Atomic force microscopy image and V-I curves suggest that the films at this thickness are still continuous. The resistivity versus temperature results imply that the conductivity mechanism in all these films is similar. The resistivity of 4 nm thick film is much greater than that of 6 and 8 nm films. The films show ferrimagnetic instead of reported superparamagnetic behavior. The dead layer formed by Mg diffusion between MgO substrate and magnetite films and also the dead layer on the top uncapped film could be the possible reasons for the anomalous resistivity and magnetic properties of the ultrathin films. The effect of the "dead layer" in the thinner film is relatively greater than the one in the thicker film and should lead to a lower magnetoresistance.

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Nonvolatile Transport States in Ferrite Thin Films Induced by Field‐Effect Involving Redox Processes

Fujiwara

Ichimura

Tanaka

2014

Adv Materials Inter

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Influence of reducing thermo-chemical treatment on magnetic properties of magnetite Fe3O4 (100) epitaxial films

Cited by 3 publications

References 7 publications

Swift heavy ion irradiation-induced modifications in structural, magnetic and electrical transport properties of epitaxial magnetite thin films

Swift heavy ion irradiation-induced modifications in structural, magnetic and electrical transport properties of epitaxial magnetite thin films

The magnetic and magnetoresistance properties of ultrathin magnetite films grown on MgO substrate

Nonvolatile Transport States in Ferrite Thin Films Induced by Field‐Effect Involving Redox Processes

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