AC magnetic susceptibility under pressure and Mössbauer effect studies of the isotropy point TIP in magnetite

Żukrowski, J.; Wiecheć, A.; Zach, R.; Tabiś, Wojciech; Tarnawski, Z.; Król, G.; Kim-Ngan, N.-T.H.; Ka̧kol, Z.; Kozłowski, A.

doi:10.1016/j.jallcom.2006.06.113

Cited by 8 publications

(8 citation statements)

References 16 publications

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“…[16] Pasternak et al [2003] claimed that accounting for a temperature dependency on the Mössbauer spectra as a signature of the Verwey transition would imply that the Verwey transition temperature increases with pressure. Because prior evidence contradicted this interpretation, the authors dismissed the possibility, which led them to propose that magnetite undergoes a coordination crossover from inverse to normal spinel: a hypothesis that became widely refuted [Gasparov et al, 2005;Klotz et al, 2006Klotz et al, , 2008Kobayashi et al, 2006;Ovsyannikov et al, 2008;Żukrowski et al, 2007]. Reinterpreting the Mössbauer spectra in light of our new data is thus not incompatible with Mössbauer and could shed light on the coordination crossover controversy.…”

Section: Discrepancy With Previous Workmentioning

confidence: 67%

“…Although these points explain the successive drop in AC susceptibility with pressure, they do not explain the decrease in the transition temperature [ Spałek et al , 2008; Tamura , 1990; Wiecheć et al , 2005; Żukrowski et al , 2007]. However, the heating experiment on slightly oxidized sample 3.87‐h and the relatively long time between stress treatment and measurement suggest that memory of the high‐pressure signal is retained in the decompressed material.…”

Section: Discussionmentioning

confidence: 99%

“…[15] Until now, physical measurements have universally shown that the Verwey transition temperature decreases with pressure [Gasparov et al, 2005;Kakudate et al, 1979;Môri et al, 2002;Pasternak et al, 2003;Ramasesha et al, 1994;Rozenberg et al, 1996;Rozenberg et al, 2006;Rozenberg et al, 2007;Samara, 1968;Tamura, 1990;Todo et al, 2001;Wiecheć et al, 2005;Żukrowski et al, 2007]. So why do we find the opposite?…”

Section: Discrepancy With Previous Workmentioning

confidence: 99%

“…They instead interpreted the data as being due to a coordination crossover in which magnetite's structure changes from inverse to normal spinel. Several workers have now found evidence contradictory to this hypothesis [ Gasparov et al , 2005; Klotz et al , 2006, 2008; Kobayashi et al , 2006; Ovsyannikov et al , 2008; Żukrowski et al , 2007]. Thus, the physical nature responsible for the transition remains contentious.…”

Section: Introductionmentioning

confidence: 99%

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Strain memory of the Verwey transition

Carporzen¹,

Gilder²

2010

J. Geophys. Res.

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[1] We studied the effects of stress on the Verwey transition for pure, stoichiometric, synthetic multidomain magnetite and for natural multidomain magnetite having both relatively low and high degrees of oxidation. Low-temperature measurements of the magnetic moments were carried out after pressure release. Our results unambiguously show an increase in the Verwey transition temperature with increasing pressure that ranges from 1 K/GPa for stoichiometric magnetite to 3 K/GPa for highly oxidized magnetite for pressures up to about 5 GPa. The transition width broadens with increasing stress for stoichiometric magnetite and then becomes less broad as oxidation increases until the width is invariant with respect to stress for highly oxidized magnetite. Heat treatment to 700°C does not appreciably reverse the effect, which could make the Verwey transition suitable for use as a geobarometer in cases where high pressures (>1 GPa) are involved, such as in meteorite impact craters. A model explaining the results is put forward.

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Section: Discrepancy With Previous Workmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 99%

Section: Discrepancy With Previous Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Strain memory of the Verwey transition

Carporzen¹,

Gilder²

2010

J. Geophys. Res.

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“…was confirmed in direct structural studies [47,48]. Alternative interpretations are also possible [43]. As regards the Verwey phase, the existing data for the Verwey phase provide evidence against the normal configuration.…”

Section: Are There Any Opportunities For the Inverse → Normal Spinel mentioning

confidence: 69%

A new crossover in Fe₃O₄magnetite under pressure near 6 GPa: modification to ‘ideal’ inverse cubic spinel?

Ovsyannikov

Shchennikov

Todo

et al. 2008

J. Phys.: Condens. Matter

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The results of the first study on the thermoelectric power (Seebeck effect) of single crystals of Fe 3 O 4 magnetite at high pressure P up to 20 GPa and room temperature are reported. The electrical resistance and a sample's contraction (relative compressibility) were also investigated over a P range of 0-20 GPa. A smooth bend (crossover) in the pressure dependence of the thermopower was firmly established near 6 GPa. This feature was attributed to a modification of Fe 3 O 4 to an 'ideal' inverse configuration, the case where equivalent amounts of charges (the Fe 2+ ions) and vacancies (the Fe 3+ ions) at the octahedral sites provide nearly metallic polaron hopping conductivity via the octahedral network. The origin of this transformation might lie in (i) a P-tuning 'perfection' of the electronic transport in the inverse spinel, and/or in (ii) a transfer of a minor group of the charges from the tetrahedral sites to the octahedral ones, i.e. a normal → inverse configuration transition. Opportunities for the opposite valence transition in magnetite, from the inverse spinel to the normal (direct) one, are also discussed. At ambient pressure the samples of Fe 3 O 4 were probed by Raman spectroscopy and using the electrical resistivity across the Verwey transition.

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Electronic and magnetic properties of ultra-thin epitaxial magnetite films on MgO(001)

Zając¹,

Freindl²,

Ślęzak³

et al. 2011

Thin Solid Films

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AC magnetic susceptibility under pressure and Mössbauer effect studies of the isotropy point TIP in magnetite

Cited by 8 publications

References 16 publications

Strain memory of the Verwey transition

Strain memory of the Verwey transition

A new crossover in Fe₃O₄magnetite under pressure near 6 GPa: modification to ‘ideal’ inverse cubic spinel?

Electronic and magnetic properties of ultra-thin epitaxial magnetite films on MgO(001)

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AC magnetic susceptibility under pressure and Mössbauer effect studies of the isotropy point TIP in magnetite

Cited by 8 publications

References 16 publications

Strain memory of the Verwey transition

Strain memory of the Verwey transition

A new crossover in Fe3O4magnetite under pressure near 6 GPa: modification to ‘ideal’ inverse cubic spinel?

Electronic and magnetic properties of ultra-thin epitaxial magnetite films on MgO(001)

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Product

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A new crossover in Fe₃O₄magnetite under pressure near 6 GPa: modification to ‘ideal’ inverse cubic spinel?