Electron Spin Resonance across the Charge-ordering Transition in YBaMn2O6

Abstract

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.

6 pages, 4 figures, submitted to PRB

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Cited by in corpus (5)

• Korringa-like relaxation in the high-temperature phase of A-site ordered YBaMn2O6
• Magnetic fluctuations and superconductivity in Fe pnictides probed by electron spin resonance
• Electron spin resonance and exchange paths in the orthorhombic dimer system Sr2VO4
• Transverse spin relaxation and magnetic correlation in $P{r}_{1-x}C{a}_{x}Mn{O}_3$ : influence of particle size variation and chemical doping
• muSR Investigation of magnetically ordered states in A-site ordered perovskite manganites RBaMn2O6 (R = Y and La)