Magnetic ordering in the fine particles of some bulk Pauli-paramgnets

TL;DR

This study investigates how reducing bulk Pauli-paramagnets to fine particles via ball-milling induces magnetic ordering, revealing ferromagnetic features at room temperature and magnetic order in Kondo lattice systems at low temperatures.

Contribution

It demonstrates that magnetic ordering can be induced in fine particles of enhanced Pauli paramagnets, a phenomenon not observed in their bulk forms, suggesting widespread effects.

Findings

Co systems show ferromagnetic features at room temperature.

CeRu2Si2 exhibits magnetic order below 8 K in fine particles.

Magnetic moments are large enough to exclude surface effects.

Abstract

Fine particles of some of the extensively studied 'enhanced' Pauli paramagnets - LuCo2, ScCo2, ZrCo2 and CeRu2Si2, have been prepared by high-energy ball-milling and investigated for their magnetic behavior. In the case of Co systems, these particles show ferromagnetic features even at room temperature. In the case of CeRu2Si2, a well-known Kondo lattice which is non-magnetic in the bulk form, features attributable to the onset of magnetic order below about 8 K could be seen in the fine particles. The magnitudes of the magnetic moment of these small particles at high fields are sufficiently large to conclude that the observed magnetic ordering is not just a surface effect. This transformation to magnetic ordering in small particles could be widespread among enhanced Pauli paramagnets.