# Single-particle versus collective effects in assemblies of nanomagnets: screening

## TL;DR

This paper investigates how surface effects can suppress dipolar interactions in nanomagnet assemblies, causing them to behave as noninteracting systems, with implications for understanding their magnetic properties.

## Contribution

It provides a formalism to identify conditions under which surface effects screen dipolar interactions in nanomagnet assemblies.

## Key findings

- Surface effects can effectively screen dipolar interactions.
- Screening influences observable magnetic properties.
- The formalism applies to equilibrium magnetization, ac susceptibility, and ferromagnetic resonance.

## Abstract

We discuss experimentally realizable situations in which surface effects may "screen out" the dipolar interactions in an assembly of nanomagnets, which then behaves as a noninteracting system. We consider three examples of physical observables, equilibrium magnetization, ac susceptibility and ferromagnetic resonance spectrum, to illustrate this screening effect. For this purpose, we summarize the formalism that accounts for both the intrinsic features of the nanomagnets and their collective effects within an assembly the condition for screening.