Bertaina S, Pashchenko V A, Stepanov A, Masuda T, Uchinokura K
Laboratoire Matériaux et Microélectronique de Provence, associé au CNRS, Case-142, Université d'Aix-Marseille III, 13397 Marseille Cedex 20, France.
Phys Rev Lett. 2004 Feb 6;92(5):057203. doi: 10.1103/PhysRevLett.92.057203.
We have investigated the electron spin resonance (ESR) on single crystals of BaCu2Ge2O7 at temperatures between 300 and 2 K and in a large frequency band, 9.6-134 GHz, in order to test the predictions of a recent theory, proposed by Oshikawa and Affleck (OA) [Phys. Rev. Lett. 82, 5136 (1999)]], which describes the ESR in a spin-1/2 Heisenberg chain with the Dzyaloshinskii-Moriya interaction. We find, in particular, that the ESR linewidth, Delta H, displays a rich temperature behavior. As the temperature decreases from T(max)/2 approximately 170 to 50 K, Delta H shows a rapid and linear decrease, Delta H approximately T. At low temperatures, below 50 K, Delta H acquires a strong dependence on the magnetic field orientation and for H axially c it shows a (h/T)(2) behavior which is due to an induced staggered field h, according to OA's prediction.
我们研究了BaCu2Ge2O7单晶在300至2 K温度范围内以及9.6 - 134 GHz的大频率波段下的电子自旋共振（ESR），以检验由Oshikawa和Affleck（OA）[《物理评论快报》82, 5136 (1999)]提出的近期理论的预测，该理论描述了具有Dzyaloshinskii - Moriya相互作用的自旋 - 1/2海森堡链中的ESR。我们特别发现，ESR线宽ΔH呈现出丰富的温度行为。当温度从约170 K的T(max)/2降至50 K时，ΔH迅速且线性下降，ΔH∝T。在低温下，低于50 K时，ΔH对磁场取向有强烈依赖性，对于沿c轴方向的磁场H，它呈现出(h/T)²行为，这是根据OA的预测，由诱导的交错场h导致的。
