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Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Itinerant ferromagnetism in the electronic localization limit.
N Kurzweil1, E Kogan, A Frydman
1The Department of Physics, Bar Ilan University, Ramat Gan 52900, Israel.
Physical Review Letters
|April 28, 2009
Summary
Ultrathin films of nickel, cobalt, and iron exhibit ferromagnetism only below a critical resistance. Above this threshold, electronic disorder likely suppresses spontaneous magnetism in these materials.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Magnetism
Background:
- Understanding the magnetic properties of ultrathin transition metal films is crucial for developing advanced magnetic devices.
- Ferromagnetism in nanoscale materials can be significantly influenced by film thickness, surface effects, and electronic structure.
Purpose of the Study:
- To investigate the critical thickness and resistance thresholds for ferromagnetism in ultrathin Ni, Co, and Fe films.
- To explore the relationship between electronic disorder and the suppression of spontaneous magnetism in these films.
Main Methods:
- Hall effect (Rxy(H)) and magnetoresistance (Rxx(H)) measurements were performed on ultrathin films.
- Film thicknesses ranged from 0.2 to 8 nm, with resistances from 1 MΩ to 100 Ω.
Main Results:
- Films with resistance above a critical value (RC) and thickness below a critical value (dC) showed no ferromagnetism.
- Ferromagnetism was observed only in films with resistance below RC, which is material-dependent.
- A correlation between electronic disorder and the absence of ferromagnetism was noted.
Conclusions:
- A critical resistance value (RC) determines the onset of ferromagnetism in ultrathin Ni, Co, and Fe films.
- Electronic disorder in the strong localization regime may suppress itinerant ferromagnetism in these films.
- The findings provide insights into the fundamental mechanisms governing magnetism in nanoscale materials.
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