Effects of dilution on magnetic and transport properties of La0.7Ca0.3Mn1-xM'xO3
| Autor: | Nam, D. N. H., Hong, H. S., Khien, N. V., Dai, N. V., Thanh, T. D., Tuong, L. T. C., Hong, L. V., Phuc, N. X. |
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| Rok vydání: | 2008 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Magnetic and transport properties of La0.7Ca0.3Mn1-xM'xO3 (M'=Al,Ti) are studied. The dilution of the Mn lattice results in a weakening of the ferromagnetism, a deterioration of the metallic conductivity, and a strong enhancement of the magnetoresistance. Although Tc linearly decreases with x in the low substitution ranges for both M' series, the scaling behavior Tc(np) previously observed for La0.7Sr0.3Mn1-xM'xO3 [Phys. Rev. B 73, 184403 (2006)] is no longer obtained. Extrapolations of the Tc(np) linear curves to Tc=0 give np values much smaller than 1. These results suggest that, according to a molecular-field approximation, antiferromagnetic superexchange between Mn ions is significant in La0.7Ca0.3MnO3, in contrast to what observed in La0.7Sr0.3MnO3. Additionally, structural data of the Al-substituted samples suggest that variations of the eg-electron bandwidth W cannot explain the decrease of Tc in magnetically diluted manganites. Comment: Revtex 4, 5 pages, 5 figures |
| Databáze: | arXiv |
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