Reentrant spin-glass state and magnetodielectric effect in the spiral magnetBiMnFe2O6
| Autor: | Kyongjun Yoo, A. Sundaresan, Byung-Gu Jeon, Somnath Ghara, Kee Hoon Kim |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Physical Review B. 90 |
| ISSN: | 1550-235X 1098-0121 |
| Popis: | The complex oxide $\mathrm{Bi}\mathrm{Mn}{\mathrm{Fe}}_{2}{\mathrm{O}}_{6}$ crystallizing in a centrosymmetric orthorhombic structure ($Pbcm$) is known to exhibit a spiral antiferromagnetic ordering at ${T}_{N}\ensuremath{\sim}212$ K and an anomaly in magnetization at low temperature (${T}_{P}\ensuremath{\sim}34$ K). To understand the origin of the low temperature anomaly and to verify experimentally whether or not the spiral magnetism induces ferroelectricity, we have carried out detailed magnetization and electrical measurements on a polycrystalline sample. Frequency-dependent ac susceptibility, dc magnetic memory effect, and dc magnetization relaxation studies show that the low temperature anomaly at ${T}_{P}$ is associated with a reentrant spin-glass transition. From dc magnetization, we found that there exists another distinct temperature (${T}_{\text{irr}}$), which corresponds to a strong thermomagnetic irreversibility. The field dependence of these two temperatures, ${T}_{P}(H)$ and ${T}_{\text{irr}}(H)$, follow Gabay-Toulouse and de Almeida--Thouless lines, respectively, which are indicative of the Heisenberg spin-glass state. We also observe another magnetic anomaly at ${T}^{*}\ensuremath{\sim}170$ K, where a dielectric anomaly with a significant magnetocapacitance effect is observed. However, pyroelectric current and positive-up-negative-down measurements reveal the absence of ferroelectricity in this compound. |
| Databáze: | OpenAIRE |
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