Magnetism in iron-rich 2D phyllosilicates

Aleksandar Matkovic

Montanuniversity Leoben
Institute of Physics

Tuesday, 11th October 2022,16:00 s.t.

The talk will be given in hybrid mode.

You can either attend in physical presence:
TU Wien, Institute of Applied Physics,
Wiedner Hauptstraße 8-10, 1040 Vienna
Yellow Tower “B”, Seminar Room DB 05 B (5th floor)

Or you join via Zoom:
Meeting ID: 994 4507 9914    Passcode: zy6drsJy

Magnetism in iron-rich 2D phyllosilicates

Driven mainly by the potential applications in spintronics, memory, and sensing, magnetic van der Waals materials have attracted attention in the last years. While the field focuses mainly on layered iodides/tellurides and diluted layered magnetic semiconductors, the class of magnetic phyllosilicates remain almost completely unexplored. The mineral class of phyllosilicates (layered silicates) counts more than 240 members, and many of these minerals are known to incorporate local magnetic moment baring ions as Fe/Ni/Co which substitute Mg/Al sites in the central octahedral group. These naturally occurring magnetic van der Waals materials could serve as a novel and versatile platform for 2D magnetic insulators. This talk will present our recent findings on layered magnetic minerals, mainly focusing on iron-rich talc (Fe:talc) [1] and iron-micas, including their iron end-members annite, and minnesotaite. These systems can serve as scaffolds to incorporate local magnetic moment baring ions in high concentration. Capping silicate/aluminate tetrahedral groups in their monolayers enable ambient stability, while magnetic properties could be tailored in the central octahedral site of the monolayers.

Figure 1 – Iron-rich talc:
(a) Fe:talc flakes exfoliated on SiO 2/Si (inset AFM topography of a monolayer).
(b) step-edge cross-
section with the side-view of the structural model.
(c) top view of the Fe:talc-structure.
(d) Raman spectra of the Mg/Fe-OH
(e) WDS quantitative analysis of Fe-concentration.
(f) SEAD of a suspended flake after over two years of ambient storing.