Tunable Magnetic Order in Fe-Mg Codoped Montmorillonite Nanoclay Interfaced with Amino Acids

Area of Science:

• Materials Science
• Nanotechnology
• Computational Chemistry

Background:

• Montmorillonite (MMT) nanoclay is explored for its potential in advanced applications.
• Fe-Mg codoping introduces magnetic properties to MMT nanoclay.
• Unnatural amino acids (AAs) act as intercalating agents, forming MMT nanoplates.

Purpose of the Study:

• To investigate the sensitivity of the spin magnetic moment of Fe-Mg codoped MMT nanoclay.
• To understand the interactions between MMT nanoclay and three unnatural amino acids (5-aminovaleric acid, 2-aminopimelic acid, DL-2-aminocaprylic acid).
• To explore the influence of aqueous environments on these interactions and magnetic properties.

Main Methods:

• Spin-polarized density functional theory (SP-DFT) calculations were employed.
• Investigated the effect of Fe and Mg impurity positions within the MMT lattice.
• Analyzed the alignment of AA molecules on the nanoclay surface and charge transfer dynamics.

Main Results:

• Strong electrostatic interactions observed due to substantial charge transfer between AAs and MMT.
• AA molecules stabilize Fe(II), preventing oxidation to Fe(III), highlighting clay-amino acid interaction significance.
• Predicted tunable magnetic orders (ferromagnetic, antiferromagnetic, ferrimagnetic) influenced by AA-MMT interactions in vacuum and aqueous media.

Conclusions:

• The study demonstrates tunable magnetic properties of Fe-Mg codoped MMT nanoclay through interactions with unnatural amino acids.
• Significant magnetic exchange coupling in aqueous media suggests potential as quantum ferrofluids.
• Findings point to promising biomedical and bioengineering applications, including magnetic imaging, drug targeting, and sensors.