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Electron spin resonance in the $S$=1/2 quasi-one-dimensional antiferromagnet with Dzyaloshinskii-Moriya interaction BaCu$\_2$Ge$\_2$O$\_7$

Sylvain Bertaina·V. A. Pashchenko·Anatoli Stepanov·T. Masuda·K. Uchinokura
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Abstract

We have investigated the electron spin resonance (ESR) on single crystals of BaCu$\_2$Ge$\_2$O$\_7$ 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), which describes the ESR in a $S$=1/2 Heisenberg chain with the Dzyaloshinskii-Moriya interaction. We find, in particular, that the ESR linewidth, $ΔH$, displays a rich temperature behavior. As the temperature decreases from $T\_{max}/2\approx $ 170 K to 50 K, $ΔH$ shows a rapid and linear decrease, $ΔH \sim T$. At low temperatures, below 50 K, $ΔH$ acquires a strong dependence on the magnetic field orientation and for $H \| c$ it shows a $(h/T)^2$ behavior which is due to an induced staggered field $h$, according to OA's prediction.

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Sylvain Bertaina, V. A. Pashchenko, Anatoli Stepanov, T. Masuda, K. Uchinokura. 2005-01-20. Electron spin resonance in the $S$=1/2 quasi-one-dimensional antiferromagnet with Dzyaloshinskii-Moriya interaction BaCu$\_2$Ge$\_2$O$\_7$. https://doi.org/10.1103/physrevlett.92.057203

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