Spin texture induced by non-magnetic doping and spin dynamics in 2D triangular lattice antiferromagnet h-Y(Mn,Al)O3

Pyeongjae Park,Je-Geun Park,S.-W Cheong,Hasung Sim,Kazuki Iida,Ki Hoon Lee,Kirrily C Rule,Hyungje Woo,Kisoo Park,A L Chernyshev,M E Zhitomirsky,Kazuya Kamazawa,Joosung Oh,Jaehong Jeong,T G Perring,Taehun Kim,Jonathan C Leiner

doi:10.1038/s41467-021-22569-3

Abstract

Novel effects induced by nonmagnetic impurities in frustrated magnets and quantum spin liquid represent a highly nontrivial and interesting problem. A theoretical proposal of extended modulated spin structures induced by doping of such magnets, distinct from the well-known skyrmions has attracted significant interest. Here, we demonstrate that nonmagnetic impurities can produce such extended spin structures in h-YMnO3, a triangular antiferromagnet with noncollinear magnetic order. Using inelastic neutron scattering (INS), we measured the full dynamical structure factor in Al-doped h-YMnO3 and confirmed the presence of magnon damping with a clear momentum dependence. Our theoretical calculations can reproduce the key features of the INS data, supporting the formation of the proposed spin textures. As such, our study provides the first experimental confirmation of the impurity-induced spin textures. It offers new insights and understanding of the impurity effects in a broad class of noncollinear magnetic systems.

Highlights

Novel effects induced by nonmagnetic impurities in frustrated magnets and quantum spin liquid represent a highly nontrivial and interesting problem
Extensive search for a genuine quantum spin liquid (QSL) state in frustrated magnets has been consistently plagued by the impurity issues, e.g., herbertsmithite and YbMgGaO4 as the S = 1/2 kagome[1,2,3] and triangular[4,5,6] QSL candidates, respectively
It has been theoretically pointed out that impurities themselves can induce continuum-like excitations in geometrically frustrated magnets, which is difficult to distinguish from the genuine signature of a QSL state

Summary

Introduction

Novel effects induced by nonmagnetic impurities in frustrated magnets and quantum spin liquid represent a highly nontrivial and interesting problem. H-YMn1-xAlxO3 is a unique model system to study dilution effects in a frustrated magnet, where non-magnetic Al3+ ions d–f Theoretical INS cross-section of d h-YMnO3, e h-YMn0.9Al0.1O3, and f h-YMn0.85Al0.15O3, which include the instrumental resolution convolution as well as the data integration effect over the c∗-axis (see Methods).

Results

Conclusion