Presentation Title

Synthesis and Magnetic Characterization of Greigite Fe3S4

Faculty Mentor

Stephen Tsui

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 114

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Greigite (Fe3S4) is a naturally occurring iron sulfide mineral with the same crystal structure as its oxide counterpart magnetite (Fe3O4). Magnetite has long been characterized to be ferrimagnetic and possesses a structural phase transition at 122 K. Above this Verwey transition, magnetite behaves as a semimetal with a cubic spinel structure. Below 122 K, the material behaves as an insulator with a monoclinic structure. Since magnetite and greigite have the same lattice structure, it is theorized that greigite should also exhibit this Verwey transition. However, experimental evidence of this is lacking.

In this investigation, we synthesized greigite through a solution-based route and characterized its magnetic properties using vibrating sample magnetometry. The Verwey transition was not observed, but the magnetization data did reveal an antiferromagnetic type of behavior with a slope change near 100 K. It has been reported that a crossover from insulator to metallic behavior occurs in greigite near 100 K, and more work including our own resistivity and heat capacity measurements needs to be done to verify the correlation between the magnetic data and this crossover in electrical conduction behavior.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Synthesis and Magnetic Characterization of Greigite Fe3S4

CREVELING 114

Greigite (Fe3S4) is a naturally occurring iron sulfide mineral with the same crystal structure as its oxide counterpart magnetite (Fe3O4). Magnetite has long been characterized to be ferrimagnetic and possesses a structural phase transition at 122 K. Above this Verwey transition, magnetite behaves as a semimetal with a cubic spinel structure. Below 122 K, the material behaves as an insulator with a monoclinic structure. Since magnetite and greigite have the same lattice structure, it is theorized that greigite should also exhibit this Verwey transition. However, experimental evidence of this is lacking.

In this investigation, we synthesized greigite through a solution-based route and characterized its magnetic properties using vibrating sample magnetometry. The Verwey transition was not observed, but the magnetization data did reveal an antiferromagnetic type of behavior with a slope change near 100 K. It has been reported that a crossover from insulator to metallic behavior occurs in greigite near 100 K, and more work including our own resistivity and heat capacity measurements needs to be done to verify the correlation between the magnetic data and this crossover in electrical conduction behavior.