Wednesday, April 3, 2013

1304.0300 (Weiwei Li et al.)

Oxygen-Vacancy-Induced Antiferromagnetism to Ferromagnetism
Transformation in Multiferroic Thin Films
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Weiwei Li, Run Zhao, Le Wang, Rujun Tang, Yuanyuan Zhu, Joo Hwan Lee, Haixia Cao, Tianyi Cai, Haizhong Guo, Can Wang, Langsheng Ling, Li Pi, Kuijuan Jin, Yuheng Zhang, Haiyan Wang, Yongqiang Wang, Sheng Ju, Hao Yang
Oxygen vacancies (VOs) effects on magnetic ordering in Eu0.5Ba0.5TiO3-{\delta} (EBTO3-{\delta}) thin films have been investigated using a combination of experimental measurements and first-principles density-functional calculations. Two kinds of EBTO3-{\delta}thin films with different oxygen deficiency have been fabricated. A nuclear resonance backscattering spectrometry technique has been used to quantitatively measure contents of the VOs. Eu0.5Ba0.5TiO3 ceramics have been known to exhibit ferroelectric (FE) and G-type antiferromagnetic (AFM) properties. While, a ferromagnetic (FM) behavior with a Curie temperature of 1.85 K has been found in the EBTO3-{\delta} thin films. Spin-polarized Ti3+ ions, which originated from the VOs, has been proven to mediate a FM coupling between the local Eu 4f spins and were believed to be responsible for the great change of the magnetic ordering. Our work opens up a new avenue for developing FM-FE materials by manipulating the oxygen deficiency in AFM-FE multiferroics.
View original: http://arxiv.org/abs/1304.0300

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