Low temperature ESR in spin ladder (C7H10N)2Cu(1−x)ZnxBr4

Yu V Krasnikova,K Yu Povarov,S Galeski,A Zheludev,D Schmidiger,V N Glazkov,M A Fayzullin

doi:10.1088/1742-6596/969/1/012113

Abstract

Spin-gap magnet (C7H10N)2Cu(1−x)ZnxBr4 (DIMPY) is an example of a strong-leg spin ladder. We report here the results of the ESR study of pure and diamagnetically diluted DIMPY. ESR study of the pure system (x=0) revealed that the spin dynamics of DIMPY is affected by uniform Dzyaloshinskii-Moriya (DM) interaction. We observe narrowing of the ESR absorption line in diamagnetically diluted DIMPY pointing to suppression of DM channel of spin relaxation by doping.

Highlights

Spin ladder is a model low-dimensional spin system
We report here the results of the ESR study of pure and diamagnetically diluted DIMPY
ESR study of the pure system (x=0) revealed that the spin dynamics of DIMPY is affected by uniform Dzyaloshinskii-Moriya (DM) interaction

Summary

Introduction

Spin ladder is a model low-dimensional spin system. It consists of two spin chains (called ‘legs’) coupled by interchain exchange bonds (which are the ‘rungs’ of spin ladder). The ESR method has high energy resolution (about 0.005 meV) and it could be used to detect weak anisotropic spin-spin interactions Such anisotropic spin-spin interactions exist in our system: DIMPY crystal symmetry allows Dzyaloshinskii-Moriya (DM) interaction. Because of translation and inversion symmetry present, DM interaction is forbidden on the rungs of the ladder, it is uniform along the leg of the ladder and has a different sign on different legs (figure 1) This allows to build a compact microscopic model which includes two exchange coupling constants and three components of DM vector only:. Here i counts spins along the leg of the ladder and a, b are legs’ indices Solving such a model remains a challenge, but supposedly it should yield both the fine structure of the excitations spectrum and relaxation of the spin excitations due to anisotropic spin-spin interactions. We observe that diamagnetic dilution results in the narrowing of ESR absorption line, i. e. that introduction of structural disorder increases quasiparticles lifetime

34.56 GHz 13

ESR in Zn-doped DIMPY