arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.1641cond-mat.str-elcond-mat.mtrl-sci
收藏

YBaMn2O6中电荷有序跃迁的电子自旋共振

Electron Spin Resonance across the Charge-ordering Transition in YBaMn2O6

D. Zakharov, J. Deisenhofer, H. -A. Krug von Nidda, T. Nakajima, Y. Ueda, A. Loidl

摘要:

采用顺磁电子自旋共振(ESR)方法研究了金属有序锰氧化物YBaMn 2 O 6的电荷有序和结构相变,温度分别为480 K和520 K.所有ESR参数在T_t处都表现出跳跃式变化,而在T_CO处的电荷有序仅表现为一个微弱而广泛的异常。在T_t以上,ESR自旋磁化率相对于直流磁化率降低,表明只有Mn离子的t_2g核自旋对共振吸收有贡献。e_g自旋的贡献被e_g电子的极化跃迁过程的时间尺度所抑制。在这个制度的线宽是让人想起一个Korringa型弛豫行为。在这幅图中,T_t以下的ESR性质主要是由极化子跃迁过程的减慢所决定的。电荷波动持续到温度T* ~ 410 K,低于该温度,该系统可以被描述为Mn $^{3+}$和Mn $^{4+}$自旋的电荷有序组装。

英文摘要:

We investigated the metal-ordered manganite system YBaMn2O6 using electron spin resonance (ESR) in the paramagnetic regime across the charge-ordering and structural phase transition at T_CO = 480 K and T_t = 520 K, respectively. All ESR parameters exhibit jump-like changes at T_t while the charge-ordering at T_CO manifests itself only as a weak and broad anomaly. Above T_t the ESR spin susceptibility is reduced with respect to the dc-susceptibility, indicating that only the t_2g-core spins of Mn ions contribute to the resonance absorption. The contribution of the e_g-spins is suppressed by the time scale of the polaronic hopping process of the e_g-electrons. The linewidth in this regime is reminiscent of a Korringa-type relaxation behavior. In this picture the ESR properties below T_t are dominated by the slowing down of the polaronic hopping process. The charge fluctuations persist down to the temperature T* ~ 410 K, below which the system can be described as a charge-ordered assembly of Mn$^{3+}$ and Mn$^{4+}$ spins.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑