Emergence Of Ferromagnetism In Nanoparticles Of Antiferromagnetic Nd0.4Sr0.6MnO3

TL;DR

This study demonstrates that reducing the grain size of Nd0.4Sr0.6MnO3 from bulk to nanoscale induces a transition from antiferromagnetic to ferromagnetic behavior, highlighting surface disorder and pressure effects as key factors.

Contribution

It reveals the emergence of ferromagnetism in nanoparticles of an antiferromagnetic material, a phenomenon not observed in the bulk form.

Findings

Ferromagnetism appears as grain size decreases to 40 nm.

Enhanced ferromagnetic behavior with smaller grains.

Large coercivity and magnetic irreversibility observed.

Abstract

We have investigated the magnetic state of Nd0.4Sr0.6MnO3 with the variation of its grain size down to average nanometric diameter (40 nm). The bulk sample is antiferromagnetic (AFM) in nature. However, on reduction of the grain size, emergence of ferromagnetic behavior is experimentally observed. Linear and nonlinear ac magnetic susceptibility measurements reveal that ferromagnetic nature is enhanced as the grain size is reduced. Large coercivity and bifurcation between zero field cooled and field cooled magnetization curves indicate an intrinsic disorder and large anisotropy in the system. Observed behaviors are attributed to surface disorder as well as to possible pressure effect on nano grains.