Synthesis of Antiferromagnetic Macromolecular Particles

Abstract

KMnF₃ and NaMnF₃ in bulk are antiferromagnets with a T_N of 88.3 K and 66 K respectively. Each are easily precipitated by mixing excess NaF or KF and MnC1₂. This same reaction can be carried out in the water pools of reverse micelles. By using dioctyl sulfosuccinate (AOT) and isooctane, reverse micelles can be made with a water pool of a specific size controlled by the water/surfactant ratio. This combination of oil phase, surfactant, and aqueous solutions allows a unique opportunity for the fabrication for macromolecular sized materials with narrow size distributions. Using the reverse micelle technique, we synthesized 30 nm particles of NaMnF₃ and KMnF₃. The particles have a narrow size distribution of <10% verified by TEM. Temperature and field dependent magnetic properties will be discussed.

Key Words:

• antiferromagnet
• reverse micelle
• nanoparticles