Fe5−xGe2Te2—a New Exfoliable Itinerant Ferromagnet with High Curie Temperature and Large Perpendicular Magnetic Anisotropy

Jothi, Palani Raja; Scheifers, Jan P.; Zhang, Yuemei; Alghamdi, Mohammed S; Stekovic, Dejan; Itkis, Mikhail E.; Fokwa, Boniface P. T.

doi:10.1002/pssr.201900666

Cited by 12 publications

(8 citation statements)

References 36 publications

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“…1−3 In the past few years, various bulk vdW ferromagnets have been discovered, including Cr(Si,Ge)Te 3 , 3−6 Cr-(Br,I) 3 , 3,6−8 Fe n GeTe 2 (3 ≤ n ≤ 5), 9−20 and Fe 2 Ge 2 Te 2 . 21 In these vdW ferromagnets, the magnetic interaction is mainly generated within the 2D plane, while it is weak between layers. Such magnetic vdW materials can be exfoliated to obtain a monolayer in which the strong magnetic anisotropy stabilizes a long magnetic order.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Two-dimensional (2D) van der Waals (vdW) materials have been widely utilized to explore unique phenomena in the 2D limit. − In the past few years, various bulk vdW ferromagnets have been discovered, including Cr(Si,Ge)Te 3 , − Cr(Br,I) 3 , ,− Fe n GeTe 2 (3 ≤ n ≤ 5), − and Fe 2 Ge 2 Te 2 . In these vdW ferromagnets, the magnetic interaction is mainly generated within the 2D plane, while it is weak between layers.…”

Section: Introductionmentioning

confidence: 99%

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Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Eguchi,

Ikeda,

Yamamoto

et al. 2023

Inorg. Chem.

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Fe 5−x GeTe 2 is a two-dimensional van der Waals material that exhibits ferromagnetic order with a high Curie temperature (T C ) of around room temperature. In addition to T C , two magnetic transitions occur with decreasing temperature, and a charge-ordered state is observed at low temperatures. We employed Ge Kα X-ray fluorescence holography (XFH) for Fe 5−x GeTe 2 to directly investigate the local structure in the charge-ordered state, i.e., the × 3 3 superstructure. The Ge Kα XFH results revealed local atomic structures around the Ge atom, thus clarifying the simultaneous locations and arrangements of the Te, Fe, and Ge atoms. The atomic positions relative to the Ge atom are useful for understanding the coexistence of the ideal 1 × 1 structure and × 3 3 superstructure found in the chargeordered state.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Eguchi,

Ikeda,

Yamamoto

et al. 2023

Inorg. Chem.

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“…The FG2T sample was synthesized via our previous method [14] through a solid‐state reaction [check the SI for details]. The as‐grown crystals were characterized by powder X‐ray diffraction (PXRD) for their phase purity (Figure 1a), scanning electron microscope (SEM) for their morphology, and energy dispersive X‐ray spectroscopy (EDS) mapping (Figure 1b) for elemental distribution.…”

Section: Figurementioning

confidence: 99%

Fe₅Ge₂Te₂: Iron‐rich Layered Chalcogenide for Highly Efficient Hydrogen Evolution

Lee

Rezaie

Luong

et al. 2022

Zeitschrift anorg allge chemie

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Recent research on van der Waals (vdW) metal chalcogenides electrocatalysts for the hydrogen evolution reaction (HER) has been devoted to finding new catalysts with active basal planes. Here, we report on experimental and theoretical investigations of the HER activity of a recently discovered iron‐rich vdW spintronic material, Fe5Ge2Te2 (FG2T) in alkaline media (1 M KOH). We show that a densified electrode of FG2T requires an overpotential of only −90.5 mV to drive a current density of 10 mA/cm2. Free energy calculations of hydrogen adsorption using density functional theory (DFT) proved that the numerous sites present on the hexagonal Te layer are more active than those found in the recently proposed Fe3GeTe2 (FGT) catalyst, supporting higher activity for the new Fe‐richer catalyst. Like in FGT, XPS analysis has found that a thin oxide layer covers the active FG2T layers, suggesting the real active surface to be a hybrid FG2T/oxide layer. These results strengthen the idea of continued screening of iron‐based vdW materials to replace the non‐abundant platinum group electrocatalysts toward HER and other electrocatalytic processes.

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“…[1, 2, 3] Of the pertinent vdW materials, several metallic Fe-Ge-Te phases possess some of the highest magnetic ordering temperatures. [4,5,6,7] Ferromagnetism in monolayer Fe 3−x GeTe 2 has been demonstrated, and of particular interest is the increase in the Curie temperature T C from ≈100 K to over 300 K caused by electrochemical gating of few-layer flakes, perhaps due to the intercalation of lithium. [8,9] Importantly, T C of bulk Fe 5−x GeTe 2 ranges from 270-310 K and can be further enhanced by cobalt or nickel substitution.…”

Section: Introductionmentioning

confidence: 99%

Tuning the Room Temperature Ferromagnetism in Fe5GeTe2 by Arsenic Substitution

May,

Yan,

Hermann

et al. 2021

Preprint

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In order to tune the magnetic properties of the cleavable high-Curie temperature ferromagnet Fe 5−x GeTe 2 , the effect of increasing the electron count through arsenic substitution has been investigated. Small additions of arsenic (2.5 and 5%) seemingly enhance ferromagnetic order in polycrystalline samples by quenching fluctuations on one of the three magnetic sublattices, whereas larger As concentrations decrease the ferromagnetic Curie temperature (T C ) and saturation magnetization. This work also describes the growth and characterization of Fe 4.8 AsTe 2 single crystals that are structurally analogous to Fe 5−x GeTe 2 but with some phase stability complications.Magnetization measurements reveal dominant antiferromagnetic behavior in Fe 4.8 AsTe 2 with a Néel temperature of T N ≈42 K. A field-induced spinflop below T N results in a switch from negative to positive magnetoresistance, with significant hysteresis causing butterfly-shaped resistance loops. In addition to reporting the properties of Fe 4.8 AsTe 2 , this work shows the importance of manipulating the individual magnetic sublattices in Fe 5−x GeTe 2 and motivates further efforts to control the magnetic properties in related materials by fine tuning of the Fermi energy or crystal chemistry.

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Fe_5−xGe₂Te₂—a New Exfoliable Itinerant Ferromagnet with High Curie Temperature and Large Perpendicular Magnetic Anisotropy

Cited by 12 publications

References 36 publications

Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Fe₅Ge₂Te₂: Iron‐rich Layered Chalcogenide for Highly Efficient Hydrogen Evolution

Tuning the Room Temperature Ferromagnetism in Fe5GeTe2 by Arsenic Substitution

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Fe5−xGe2Te2—a New Exfoliable Itinerant Ferromagnet with High Curie Temperature and Large Perpendicular Magnetic Anisotropy

Cited by 12 publications

References 36 publications

Observation of the Superstructure in Fe5–xGeTe2 by X-ray Fluorescence Holography

Observation of the Superstructure in Fe5–xGeTe2 by X-ray Fluorescence Holography

Fe5Ge2Te2: Iron‐rich Layered Chalcogenide for Highly Efficient Hydrogen Evolution

Tuning the Room Temperature Ferromagnetism in Fe5GeTe2 by Arsenic Substitution

Contact Info

Product

Resources

About

Fe_5−xGe₂Te₂—a New Exfoliable Itinerant Ferromagnet with High Curie Temperature and Large Perpendicular Magnetic Anisotropy

Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Observation of the Superstructure in Fe_5–xGeTe₂ by X-ray Fluorescence Holography

Fe₅Ge₂Te₂: Iron‐rich Layered Chalcogenide for Highly Efficient Hydrogen Evolution