Short-range Charge and Spin Superstructures in Doped Layered Co Perovskites
| Autor: | Sakiyama, N., Zaliznyak, I. A., Lee, S. -H., Mitsui, Y., Yoshizawa, H. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 78, 180406 (2008) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.78.180406 |
| Popis: | We have investigated cobaltite relatives of the layered perovskite cuprates and nickelates, Pr$_{2-x}$Ca$_x$CoO$_4$ ($0.39 \leq x \leq 0.73$) and La$_{2-x}$Sr$_x$CoO$_4$ ($x = 0.61$), using elastic neutron scattering. We have discovered doping-dependent incommensurate short-range ordering of charges and magnetic moments, which in cobaltites occur in the range of heavy doping, $ 0.5 \lesssim x \lesssim 0.75$. The charge order exists already at room temperature and shows no change on cooling. The incommensurability of its propagation vector, ${\bf Q}_c = (\epsilon_c,0,l)$, roughly scales with the concentration of Co$^{2+}$ ions, $\epsilon_c \sim (1-x)$. Magnetic order is only established at low T$\lesssim 40$ K and has twice larger periodicity, indicating a dominant antiferromagnetic correlation between the nearest Co$^{2+}$ spins. Comment: 4 pages 4 figures |
| Databáze: | arXiv |
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