A semiconducting layered metal-organic framework magnet

Chen Yang ,Enrique Cánovas,Ehrenfried Zschech,Friedrich Schwotzer,Zhitao Zhang,Petko St Petkov,Stefan Kaskel,Shengqiang Zhou,Zhongquan Liao,S A Bräuninger ,Mao Wang,Renhao Dong,Mischa Bonn,Marco Ballabio,Jichao Zhang,Thomas Heine,H.‐H Klauß ,Mingchao Wang,Peng Han,Xinliang Feng

doi:10.1038/s41467-019-11267-w

Abstract

The realization of ferromagnetism in semiconductors is an attractive avenue for the development of spintronic applications. Here, we report a semiconducting layered metal-organic framework (MOF), namely K3Fe2[(2,3,9,10,16,17,23,24-octahydroxy phthalocyaninato)Fe] (K3Fe2[PcFe-O8]) with spontaneous magnetization. This layered MOF features in-plane full π-d conjugation and exhibits semiconducting behavior with a room temperature carrier mobility of 15 ± 2 cm2 V−1 s−1 as determined by time-resolved Terahertz spectroscopy. Magnetization experiments and 57Fe Mössbauer spectroscopy demonstrate the presence of long-range magnetic correlations in K3Fe2[PcFe-O8] arising from the magnetic coupling between iron centers via delocalized π electrons. The sample exhibits superparamagnetic features due to a distribution of crystal size and possesses magnetic hysteresis up to 350 K. Our work sets the stage for the development of spintronic materials exploiting magnetic MOF semiconductors.

Highlights

The realization of ferromagnetism in semiconductors is an attractive avenue for the development of spintronic applications
The simultaneous realization of room temperature spontaneous magnetization and semiconducting behavior in a metal-organic framework (MOF) has not been experimentally demonstrated to date
By further optimizing the crystalline quality and increasing the crystallite size, our work presents the possibility to achieve room temperature ferromagnetism in a semiconducting layered MOF, highlighting the potential for developing a new generation of MOFs-based spintronics

Summary

Introduction

The realization of ferromagnetism in semiconductors is an attractive avenue for the development of spintronic applications. We report a semiconducting layered metal-organic framework (MOF), namely K3Fe2[(2,3,9,10,16,17,23,24-octahydroxy phthalocyaninato)Fe] (K3Fe2[PcFe-O8]) with spontaneous magnetization This layered MOF features in-plane full π-d conjugation and exhibits semiconducting behavior with a room temperature carrier mobility of 15 ± 2 cm[2] V−1 s−1 as determined by time-resolved Terahertz spectroscopy. Since the first report in 201220, conjugated MOFs with layered structures have been developed displaying high electrical conductivities (up to 105 s m−1) This class of materials has typically been constructed by linking N, O, or S ortho-disubstituted benzene, triphenylene or coronene ligands with transition metal ions, and featured with full π-d conjugation in 2D planes[20,21,22,23,24,25,26,27]. We report a conjugated K3Fe2[PcFe–O8] MOF with square lattice geometry and interplane van der Waals (vdW)

Methods

Results

Conclusion