Electron spin resonance across the charge-ordering transition in YBaMn2O6

Article

关键词: PHASE-TRANSITIONS;    EPR;    MANGANITES;    ESR;    LA1-XCA(X)MNO3;    MAGNETIZATION;    RELAXATION;   

DOI  :  10.1103/PhysRevB.78.235105

来源: SCIE

【 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 jumplike 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-*approximate to 410 K, below which the system can be described as a charge-ordered assembly of Mn3+ and Mn4+ spins.

【 授权许可】

Free