Magnetization and exchange in nonstoichiometric magnetite

Aragón, R.

doi:10.1103/physrevb.46.5328

Cited by 115 publications

(81 citation statements)

References 42 publications

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“…• , at 122 K, (Aragón et al, 1985;Aragón, 1992) is in apparent contradiction with the Verwey transition temperatures determined from SIRM(T) and χ (T ) curves and with the Curie temperatures. Moreover, the 122-K jump is observed even in the samples that do not show the 'bulk' Verwey transition (R1D24, RB127, RB145, and 410866).…”

Section: The Verwey Transitionmentioning

confidence: 66%

Magnetic properties of subaerial basalts at low temperatures

Kosterov

2014

Earth Planet Sp

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Magnetic properties have been measured as a function of temperature from 2 K to room temperature for twentyone samples of subaerial basalts of different origin and age, using an MPMS instrument. In all samples but four, titanomagnetite with a titanium content of less than 5 per cent has been determined as a dominant magnetic mineral carrying NRM from χ(T ) measurements above room temperature and Verwey transition observations. However, the new low-temperature experiments yielded evidence of the presence of another magnetic mineral in all samples. This mineral accounts for up to 70 per cent of saturation magnetization at 2 K and acquires a relatively strong but thermally unstable SIRM at this temperature. Comparison of susceptibility vs. temperature curves measured in low and high DC biasing fields reveals evidence of superparamagnetic behavior, peaks marking the effective blocking temperatures being shifted from <2 K to about 16 K by a 4.8 T DC magnetic field. At the same time, the presence of peaks in the high-field susceptibility curves indicate that the corresponding magnetic phase does not reach saturation, even in the highest field available to us. A possible candidate to account for these properties is a hemoilmenite with 8-10 mole per cent of hematite, originating from high-temperature deuteric oxidation. This is in accordance with the prevailing occurrence of exsolution lamellae within titanomagnetite grains observed in scanning electron microscopy (SEM) images.

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Section: The Verwey Transitionmentioning

confidence: 66%

Magnetic properties of subaerial basalts at low temperatures

Kosterov

2014

Earth Planet Sp

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“…10 together with some other values drawn from the literature for single crystals [19,[26][27][28][29]. The dispersion of the results can be explained by the difficulty to obtain the full stoichiometry for Fe 3 O 4 crystals.…”

Section: Unmilled Samplementioning

confidence: 71%

High field surface magnetic study of Fe₃O₄ nanoparticles

Kihal

Fillion

Bouzabata

et al. 2011

Physica Status Solidi (b)

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Magnetic properties of magnetite (Fe3O4) powders, milled for various times up to 15 h, are studied by magnetization measurements. For the starting powder, like in the bulk single crystal, the approach to magnetic saturation is mainly ruled by the usual 1/H and 1/H2 terms. But for the milled samples, as the grain size decreases, a 1/H1/2 term rises as the leading term and is interpreted in the framework of the theory of Chudnovsky et al. accounting for the effect of a random anisotropy generated near the surface, aside from a large constant high field susceptibility related to the canted spins at the surface.

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“…For Fe 3 O 4 having ferrimagnetic property, spin of the octahedral and tetrahedral Fe was set as up and down, respectively. These settings were able to generate lattice parameter of 8.405Å for bulk Fe 3 O 4 , which agree well with the experimental value (8.396Å) [35], and to reproduce the characteristic electronic features, the energy level of d states and the half-metal properties of Fe 3 O 4 [36].…”

Section: Methodsmentioning

confidence: 59%