Dynamic magnetism in the disordered hexagonal double perovskite BaTi$_{1/2}$Mn$_{1/2}$O$_{3}$
| Autor: | Cantarino, M. R., Amaral, R. P., Freitas, R. S., Ara��jo, J. C. R., Lora-Serrano, R., Luetkens, H., Baines, C., Br��uninger, S., Grinenko, V., Sarkar, R., Klauss, H. H., Andrade, E. C., Garcia, F. A. |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Popis: | Magnetic frustration and disorder are key ingredients to prevent the onset of magnetic order. In the disordered hexagonal double perovskite BaTi$_{1/2}$Mn$_{1/2}$O$_{3}$, Mn$^{4+}$ cations, with $S=3/2$ spins, can either form highly correlated states of magnetic trimers or dimers or remain as weakly interacting orphan spins. At low temperature ($T$), the dimer response is negligible, and magnetism is dominated by the trimers and orphans. To explore the role of magnetic frustration, disorder and possibly of quantum fluctuations, the low-$T$ magnetic properties of the remaining magnetic degrees of freedom of BaTi$_{1/2}$Mn$_{1/2}$O$_{3}$ are investigated. Heat-capacity data and magnetic susceptibility display no evidence for a phase transition to a magnetically ordered phase but indicate the formation of a correlated spin state. The low-temperature spin dynamics of this state is then explored by $\mu$SR experiments. The zero field $\mu^{+}$ relaxation rate data show no static magnetism down to $T=19$ mK and longitudinal field experiments support as well that dynamic magnetism persists at low $T$. Our results are interpreted in terms of a spin glass state which stems from a disordered lattice of orphans spins and trimers. A spin liquid state in BaTi$_{1/2}$Mn$_{1/2}$O$_{3}$, however, is not excluded and is also discussed. Comment: Main Text: 6 pages, 4 figures; Supplemental: 11 pages, 7 figures |
| Databáze: | OpenAIRE |
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