Cottam M G, Lockwood D J
Department of Physics and Astronomy, University of Western Ontario, London, ON, N6A 3K7, Canada.
Metrology Research Centre, National Research Council, Ottawa, ON, K1A 0R6, Canada.
Sci Rep. 2022 Aug 18;12(1):14065. doi: 10.1038/s41598-022-18073-3.
We present an experimental and theoretical study for the lattice vibrational (phonon) modes in the quasi-one-dimensional (or chain-like) antiferromagnet RbCoCl at low temperatures both above and below the two different magnetic phase transitions. Clear evidence is found for the role of spin-phonon interactions in providing a temperature-dependent contribution for the frequencies of the E and E symmetry phonons that occur with frequencies comparable to those of the spin wave excitations (magnons) in this compound. The behaviour in RbCoCl, as studied here by Raman scattering experiments, is quite different from that typically observed in rutile-structure antiferromagnets where the spin-phonon coupling has been well characterized. The theory is modified to take account of the strong Ising-like component in the spin Hamiltonian. This enables the spin-phonon coupling parameters to be deduced, with the analysis also revealing the onset of an extra frequency shift for the phonons below the transition temperature T = 28 K associated with magnetic ordering along the Co chains.
我们给出了在准一维（或链状）反铁磁体RbCoCl中，在两个不同磁相变温度之上和之下的低温下晶格振动（声子）模式的实验和理论研究。清楚地发现了自旋 - 声子相互作用在为E和E'对称声子的频率提供与温度相关贡献方面所起的作用，这些声子的频率与该化合物中自旋波激发（磁振子）的频率相当。通过拉曼散射实验在此研究的RbCoCl中的行为与在金红石结构反铁磁体中通常观察到的行为有很大不同，在金红石结构反铁磁体中自旋 - 声子耦合已得到很好的表征。对理论进行了修改以考虑自旋哈密顿量中类似伊辛的强分量。这使得能够推导出自旋 - 声子耦合参数，分析还揭示了在与沿Co链的磁有序相关的转变温度T = 28 K以下，声子出现额外的频率偏移。
