Effect of Pressure on the Néel Temperature of Magnetite

Samara, G. A.; Giardini, A. A.

doi:10.1103/physrev.186.577

Cited by 79 publications

(33 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One often neglected fact is that the Curie temperature is pressure dependent (Samara and Giardini, 1969). Experimental data show that an increase in pressure of~4 GPa will increase the Tc by 100°C(L~Tc/AP 2°K/Kbar).Thus, at the pressures at which the intrusion of the micro-melts along the PDFsisreportedtohaveoccurred(~35Gpa;Cloeteetal., 1999), the Tc would be greater than the temperature at which magnetite along the PDFs began to crystallize from a melt (Figure 5b).…”

Section: Source Of Magnetic Remanencementioning

confidence: 92%

See 1 more Smart Citation

'Super magnetic' rocks generated by shock metamorphism from the centre of the Vredefort impact structure, South Africa

Hart

Connell

Cloete

et al. 2000

South African Journal of Geology

View full text Add to dashboard Cite

A magnetic anomaly near the centre of the Vredefort impact structure is attributed to remanent magnetism associated with a large meteorite impact at~2.0 Ga. The rocks that underlie the anomaly are shocked Archaean granites, which have extremely high remanent magnetism. We propose that the high remanence derives from elongated, micron-size single-domain magnetite particles found along shock-induced planar deformation features in quartz. The magnetite particles appear to have preferred magnetic dipole orientations, and are interpreted to have been intruded along the planar deformation features under extreme P-T conditions following the impact event.

show abstract

Section: Source Of Magnetic Remanencementioning

confidence: 92%

“…In this case Tc> T 5 . Variation of Tc and Ts with pressure is taken from Samara and Giardini (1969) and Wyllie (1977), respectively. Note that blocking temperature (Tb) remains constant (Butler, 1992).…”

Section: Introductionmentioning

confidence: 99%

'Super magnetic' rocks generated by shock metamorphism from the centre of the Vredefort impact structure, South Africa

Hart

Connell

Cloete

et al. 2000

South African Journal of Geology

View full text Add to dashboard Cite

show abstract

“…We conjecture that the contraction of the lattice leads to greater cation-anion-cation bond angles and increased superexchange interactions. 28 In all four samples, the EXAFS modeling indicated the inversion parameter ␦, i.e., ͑Mn 1−␦ Fe ␦ ͒ tet ͓Mn ␦ Fe 2−␦ ͔ oct O 4 , to be higher than the 20%, typically quoted as the equilibrium value. 22 As the particle size increased, ␦ decreased from 62.9Ϯ 1.8% to 54.2Ϯ 2.3%.…”

mentioning

confidence: 98%

Large tunability of Néel temperature by growth-rate-induced cation inversion in Mn-ferrite nanoparticles

Yang

Chinnasamy

Grenèche

et al. 2009

Applied Physics Letters

View full text Add to dashboard Cite

Articles you may be interested inHigh temperature phase transformation studies in magnetite nanoparticles doped with Co2+ ion J. Appl. Phys. 112, 054320 (2012); 10.1063/1.4748318 Magnetoelectric behavior of carbonyl iron mixed Mn oxide-coated ferrite nanoparticles Control of the cation occupancies of MnZn ferrite synthesized via reverse micelles Structure and magnetic properties of rf thermally plasma synthesized Mn and Mn-Zn ferrite nanoparticles J. Appl. Phys. 93, 7495 (2003); 10.1063/1.1557953Mn-Zn ferrite with higher magnetization for temperature sensitive magnetic fluid

show abstract

“…6 it could convincingly be argued that the sharp transition marked by the magnetization increase in the low field determines T, and that the strong field magnetic moment above is just due to induced 1 magnetization of the then nearly paramagnetic crystal. However, the Curie temperature determined by this method T, = 566 f 1 "C is lower than the frequently cited literature value T, = 578 "C (Samara & Giardini 1969) and also the temperature where Sugiura's peak occurs. Because the natural crystal is not pure, its T, value is 2" lower than the Curie temperature of a 99.9 per cent pure magnetite standard determined by the same method.…”

Section: Methodsmentioning

confidence: 63%

Evidence for TRM domain wall moments?

Worm

Banerjee

1990

Geophysical Journal International

View full text Add to dashboard Cite

Multidomain ferro-and ferrimagnets carrying a thermoremanent magnetization (TRM) display a maximum in remanent magnetization just below the Curie temperature T, when continuously demagnetized in zero field. We interpret this demagnetization peak t o be indicative of the presence of TRM domain wall moments that grow in a small temperature interval (near &) upon heating where the domain wall volume increases at a rate faster than the decrease in spontaneous magnetization MSP. Hysteresis measurements in the vicinity of T, on a single crystal of magnetite show that the spontaneous magnetization may be orders of magnitude smaller than the strong field magnetization measured in Ms/ T curves. Micromagnetic calculations using experimentally determined M,,/T data suggest that the single domain (SD) threshold for magnetite can increase by more than an order of magnitude from room temperature to just below T, in support of the domain wall moment model.

show abstract

Effect of Pressure on the Néel Temperature of Magnetite

Cited by 79 publications

References 14 publications

'Super magnetic' rocks generated by shock metamorphism from the centre of the Vredefort impact structure, South Africa

'Super magnetic' rocks generated by shock metamorphism from the centre of the Vredefort impact structure, South Africa

Large tunability of Néel temperature by growth-rate-induced cation inversion in Mn-ferrite nanoparticles

Evidence for TRM domain wall moments?

Contact Info

Product

Resources

About