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Influence of nonmagnetic Al ions on magnetoresistance of double-perovskite Sr2Fe1−xAlxMoO6 (0≤x≤0.30)

journal contribution
posted on 26.09.2005, 00:00 by Yu Sui, Xianjie Wang, Jinguang Cheng, Zhiguo Liu, Jipeng Miao, Xiqiang Huang, Zhe Lu, Zhengnan Qian, Wenhui Su, Jinke Tang, C. K. Ong
The structural, magnetic, and magnetoresistance properties of the double-perovskite series Sr2Fe1−xAlxMoO6 (0≤x≤0.30) were systematically investigated in order to clarify the influence of nonmagnetic Al ions on the magnetoresistance. The structural refinements of these samples show that the degree of cationic order increases gradually from 88.5% for x=0 to 92% for x=0.30 without any change in the crystal structure. The magnetization measurements reveal that the substitution of nonmagnetic Al ion for Fe ion enhances the magnetic moment per Fe ion significantly. In addition the magnetic-field dependence of magnetization and magnetoresistance of these Sr2Fe1−xAlxMoO6 samples were all fitted excellently by taking into account the contributions from ferromagnetic-coupled Fe–O–Mo region and nonferromagnetic-coupled regions. The fitting results indicate that the low-field magnetoresistance can be greatly enhanced due to the separation of the cationic-ordered Fe–O–Mo regions by the paramagnetic Mo–O–Al–O–Mo chains introduced through Al doping. Furthermore, doping nonmagnetic Al ions also suppress the formation of antiferromagnetic Fe–O–Fe antiphase boundaries, and then lead to the improvement of cation ordering and the reduction of magnetoresistance under high field.

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ISO

eng

Language

English

Publisher

University of Wyoming. Libraries

Journal title

JOURNAL OF APPLIED PHYSICS

Collection

Faculty Publications - Physics and Astronomy

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