Regeneration of sulphate and the isotopic composition of natural sulphur

Chukrov, F.V.; Yermilova, L. P.; Churikov, V.S.; Nossik, L.P.

doi:10.1016/0009-2541(75)90089-3

Cited by 4 publications

(1 citation statement)

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“…The roughly spherical core has a diameter of 7.5 nm, and can contain a variable number of irons, up to a maximum of 4500. The oxide appears 28 structurally similar to ferrihydrite [29][30][31] .…”

Section: A Ferritinmentioning

confidence: 99%

Macroscopic quantum coherence in ferrimagnets

Chiolero

Loss

1997

Phys. Rev. B

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We study macroscopic quantum coherence (MQC) in small magnetic particles where the magnetization (in ferromagnets) or the Néel vector (in antiferromagnets) can tunnel between energy minima. We consider here the more general case of MQC in ferrimagnets by studying a model for a mesoscopic antiferromagnet with an uncompensated magnetic moment. Through semi-classical calculations we show that even a small moment has a drastic effect on MQC. In particular, there is a rapid crossover to a regime where the MQC tunnel splitting is equal to that obtained for a ferromagnet, even though the system is still an antiferromagnet for all other aspects. We calculate this tunnel splitting via instanton methods and compare it with numerical evaluations. As an application we re-examine the experimental evidence for MQC in ferritin and show that even though the uncompensated moment of ferritin is small it greatly modifies the MQC behavior. The excess spin allows us to extract values for experimental parameters without making any assumption about the classical attempt frequency, in contrast to previous fits. Finally, we also discuss the implications of our results for MQC in molecular magnets.

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Section: A Ferritinmentioning

confidence: 99%