High Magnetic Field ESR in S = 1 Skew Chain Antiferromagnet Ni2V2O7 Single Crystal

Yin Yin,Xia Xia,Ouyang Ouyang,Wang Wang,Yue Yue

doi:10.3390/cryst9090468

Abstract

We report electron spin resonance (ESR) in S = 1 skew chain antiferromagnet Ni2V2O7, which exhibits a spin-flop transition and a well-defined 1/2 magnetization plateau. The antiferromagnetic (AFM) ordering at TN = 7 K can be reflected by the temperature-dependent ESR spectra at low frequency for the easy axis. At 2 K, at the spin-flop transition fields along the easy a and b axes, anomalies are observed from the frequency‒field relationship. However, these modes cannot be understood by the conventional two-sublattice AFM resonance theory with uniaxial anisotropy. For the easy b axis, an unusual resonance mode is observed and its resonance field increases with decreasing frequency. This ESR mode becomes softening at ~8 T, corresponding to the onset of the 1/2 magnetization plateau.

Highlights

Low-dimensional spin systems have been attracting a lot of attention in condensed matter physics due to their exotic ground states and non-classical effects caused by spin fluctuation and magnetic frustration [1,2,3,4]
The recently studied vanadate oxide Ni2 V2 O7 is a good example of low-dimensional antiferromagnets; it belongs to the family of T2 X2 O7 (T = Cu, Co, Ni, Fe, Mn; X = P, As, V) [10,11,12,13,14,15,16,17]
Modes ω3 and ω4 are weak resonance modes; ω3 has a zero-field gap of 100 GHz and extrapolation of the field relationship (f‒H) relationship to a high field suggests that ω2 will become softening at Hc = 8.0

Summary

Introduction

Low-dimensional spin systems have been attracting a lot of attention in condensed matter physics due to their exotic ground states and non-classical effects caused by spin fluctuation and magnetic frustration [1,2,3,4]. The skew chains are formed by two different edge-sharing NiO6 octahedra along the c axis, which are isolated by embedding the corner-shared nonmagnetic tetrahedrons VO4. This results in a quasi-one-dimensional structural arrangement. A further increase in the magnetic field results in the appearance of a nematic-like phase and a wide 1/2 magnetization plateau starting at Hc = 5.5, 8.0, and 7.1 T along the a, b, and c axes, respectively [20]. ESR results on polycrystalline samples of demonstrate the presence of AFM resonances below Tour [19]. ESR mode at ~8 T, corresponding to the onset of the 1/2 magnetization plateau of the easy b axis

Ohigh-quality

Results and Discussion

At temperature

Kreported can be

Conclusions

High-Field