Two-sublattice description of the dimer-trimer chain compound <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Li</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Cu</mml:mi><mml:mn>5</mml:mn></mml:msub><mml:msub><mml:mi>Si</mml:mi><mml:mn>4</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>14</mml:mn></mml:msub></mml:mrow></mml:math>: High-field magnetization and ESR studies
Xu Jin, Zhongwen Ouyang, Xiaochen Liu, Tongtong Xiao, Jiaojiao Cao, Zhenxing Wang, Z. C. Xia, Wei Tong
Abstract
We carried out high magnetic field magnetization and electron spin resonance (ESR) measurements for the alternating dimer-trimer chain compound ${\mathrm{Li}}_{2}{\mathrm{Cu}}_{5}{\mathrm{Si}}_{4}{\mathrm{O}}_{14}$. The magnetization curve measured at 2 K exhibits a spin-flop transition at 2.6 T followed by a nonlinear increase in magnetization at high field up to 55 T. The antiferromagnetic ordering at ${T}_{\mathrm{N}}=22\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ is well characterized by the temperature-dependent ESR spectra, and the anisotropic $g$ factors at the paramagnetic phase are determined. Intriguingly, our frequency-dependent ESR spectra at 2 K reveal the development of two collinear antiferromagnetic sublattices with biaxial anisotropy, which is quite unusual because ${\mathrm{Li}}_{2}{\mathrm{Cu}}_{5}{\mathrm{Si}}_{4}{\mathrm{O}}_{14}$ contains five sublattices. Thus, ${\mathrm{Li}}_{2}{\mathrm{Cu}}_{5}{\mathrm{Si}}_{4}{\mathrm{O}}_{14}$ is three-dimensionally ordered and its magnetism might be described by a pseudo-two-sublattice model composed of antiferromagnetically coupled dimer-trimer groups (\ensuremath{\uparrow}\ensuremath{\uparrow}, \ensuremath{\uparrow}\ensuremath{\downarrow}\ensuremath{\uparrow}) and (\ensuremath{\downarrow}\ensuremath{\downarrow}, \ensuremath{\downarrow}\ensuremath{\uparrow}\ensuremath{\downarrow}).