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abstract: '[**High-temperature superconductivity in the iron-based materials emerges from, or sometimes coexists with, their metallic or insulating parent compound states. This is surprising since these undoped states display dramatically different antiferromagnetic (AF) spin arrangements and N$\rm \acute{e}$el temperatures. Although there is general consensus that magnetic interactions are important for superconductivity, much is still unknown concerning the microscopic origin of the magnetic states. In this review, progress in this area is summarized, focusing on recent experimental and theoretical results and discussing their microscopic implications. It is concluded that the parent compounds are in a state that is more complex than implied by a simple Fermi surface nesting scenario, and a dual description including both itinerant and localized degrees of freedom is needed to properly describe these fascinating materials.**]{}'
author:
- Pengcheng Dai
- Jiangping Hu
- Elbio Dagotto
title: 'Magnetism and its microscopic origin in iron-based high-temperature superconductors'
---

Introduction
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Soon after the discovery of high critical temperature (high-$T_c$) superconductivity in copper oxides [@bednorz], neutron scattering studies revealed that the parent compounds of these superconductors have an antiferromagnetic (AF) ground state with a simple collinear spin structure (Fig. 1a) [@vaknin; @tranquada88]. Because the associated AF spin fluctuations may be 