Spin Orientation of Hematite&amp;lt;tex&amp;gt;$(alpha hbox-hboxFe_2hboxO_3)$&amp;lt;/tex&amp;gt;Nanoparticles During the Morin Transition

Gee, S. H.; Hong, Y.-K.; Sur, Jung Chul; Erickson, D. W.; Park, M.H.; Jeffers, F.

doi:10.1109/tmag.2004.832253

Cited by 34 publications

(29 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[53] This scenario is consistent with the significant moment below the spin-flop transition observed in magnetization measurements of our 35×50 nm 2 particles (Fig. S6 in the Supporting Information), and it suggests that a degraded spin-flop transition might impact magnetochromism.…”

Section: Mechanism Of the Field-induced Color Contrast In α-Fe2o3 Nansupporting

confidence: 88%

“…This is because only a remnant of the spin-flop transition survives below the superparamagnetic limit, a situation that we already established as inconsistent with maximum spin-charge coupling. [53,58] Magnons are a type of spin wave commonly found in magnetic materials [59,60] and are typically explored with neutron and Raman scattering techniques. The two-magnon mode, in particular, is Raman-active.…”

Section: Magnetochromic Sensing Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Magnetochromic sensing and size-dependent collective excitations in iron oxide nanoparticles

et al. 2017

View full text Add to dashboard Cite

We combine optical and magneto-optical spectroscopies with complementary vibrational and magnetic property measurements to reveal finite length scale effects in nanoscale α-Fe2O3. Analysis of the d-to-d on-site excitations uncovers enhanced color contrast at particle sizes below approximately 75 nm due to size-induced changes in spin-charge coupling that are suppressed again below the superparamagnetic limit. These findings provide a general strategy for amplifying magnetochromism in α-Fe2O3 and other iron-containing nano-materials that may be useful for advanced sensing applications. We also unravel the size dependence of collective excitations in this iconic antiferromagnet.

show abstract

Section: Mechanism Of the Field-induced Color Contrast In α-Fe2o3 Nansupporting

confidence: 88%

Section: Magnetochromic Sensing Applicationsmentioning

confidence: 99%

Magnetochromic sensing and size-dependent collective excitations in iron oxide nanoparticles

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Nanoparticle hematite has been studied for many years because of its interesting magnetic properties (e.g., Bodker & Morup, 2000;Gee et al, 2004). Hematite is a weak ferromagnet between the Morin and Neel transition temperatures ($260 and $956 K, respectively, in bulk), and is subject to superparamagnetic relaxation effects as particle size decreases.…”

Section: Nanoparticle Studies Of Other Feox Materialsmentioning

confidence: 99%

Nanoparticulate Iron Oxide Minerals in Soils and Sediments: Unique Properties and Contaminant Scavenging Mechanisms

2005

View full text Add to dashboard Cite

Nanoparticulate goethite, akaganeite, hematite, ferrihydrite and schwertmannite are important constituents of soils, sediments and mine drainage outflows. These minerals have high sorption capacities for metal and anionic contaminants such as arsenic, chromium, lead, mercury and selenium. Contaminant sequestration is accomplished mainly by surface complexation, but aggregation of particles may encapsulate sorbed surface species into the multigrain interior interfaces, with significant consequences for contaminant dispersal or remediation processes. Particularly for particle sizes on the order of 1-10 nm, the sorption capacity and surface molecular structure also may differ in important ways from bulk material. We review the factors affecting geochemical reactivity of these nanophases, focusing on the ways they may remove toxins from the environment, and include recent results of studies on nanogoethite growth, aggregation and sorption processes.

show abstract

“…The magnetic properties of small hematite particles, and particularly the Morin transition, have been studied extensively [1][2][3]. It is generally accepted that the behavior of the Morin transition, i.e., the phase transition from an antiferromagnetic (AF) to a weakly ferromagnetic (WF) state in α-Fe 2 O 3 , is largely influenced by the particle size, next to foreign-element substitution.…”

Section: Introductionmentioning

confidence: 99%

“…It is generally accepted that the behavior of the Morin transition, i.e., the phase transition from an antiferromagnetic (AF) to a weakly ferromagnetic (WF) state in α-Fe 2 O 3 , is largely influenced by the particle size, next to foreign-element substitution. Comparison of the Morin transition temperature with the particle characteristics showed that smaller grain size lowers the temperature at which the Morin transition takes place [1]. De Grave et al [4,5] proved by integral low-energy electron Mössbauer spectroscopy (ILEEMS) that the local spin-flip of the Morin transition in small hematite particles obtained from goethite (few hundreds of nanometers long axis) differs at the surface Fe species from those in the bulk of the particles.…”

Section: Introductionmentioning

confidence: 99%

Surface effects in α-Fe2O3 nanoparticles studied by ILEEMS and TMS

et al. 2009

View full text Add to dashboard Cite

To understand the particular properties of thin α-Fe 2 O 3 films, hematite nanoparticles with sizes between 20 and 140 nm have been examined by integral lowenergy electron Mössbauer spectroscopy (ILEEMS) and transmission Mössbauer spectroscopy (TMS) at room temperature and 80 K. By comparing the results of both Mössbauer variants, surface effects of the Morin transition are studied. The results clearly indicate that the Morin transition takes place at higher temperature in the interior of the particles as compared to the outer layers. It is found that the lowering of the Morin transition is much stronger at the surface of smaller particles.

show abstract

Spin Orientation of Hematite<tex>$(alpha hbox-hboxFe_2hboxO_3)$</tex>Nanoparticles During the Morin Transition

Cited by 34 publications

References 10 publications

Magnetochromic sensing and size-dependent collective excitations in iron oxide nanoparticles

Magnetochromic sensing and size-dependent collective excitations in iron oxide nanoparticles

Nanoparticulate Iron Oxide Minerals in Soils and Sediments: Unique Properties and Contaminant Scavenging Mechanisms

Surface effects in α-Fe2O3 nanoparticles studied by ILEEMS and TMS

Contact Info

Product

Resources

About