中国物理B ›› 2010, Vol. 19 ›› Issue (10): 107505-107505.doi: 10.1088/1674-1056/19/10/107505
李静波1, 饶光辉1, 骆军1, 刘广耀1, 陈景然1, 梁敬魁2, 肖荫果3
Li Jing-Bo(李静波)a)†, Rao Guang-Hui(饶光辉)a), Xiao Yin-Guo(肖荫果)b), Luo Jun(骆军) a), Liu Guang-Yao(刘广耀)a), Chen Jing-Ran(陈景然) a), and Jing-Kui Liang(梁敬魁)a)c)
摘要: Different magnetodielectric effects were observed in Bi1-xGdxFeO3 ceramics depending on gadolinium content. A positive one was observed in the samples with x ≤ 0.10 at 295 K and 16 K, and a negative one in the sample with x = 0.4 at 16 K. Structure analysis by x-ray diffraction (XRD) reveals that the samples crystallize in the R3c structure (ferroelectrics) for x < 0.08 and in the Pbnm structure (paraelectrics) for x ≥ 0.3 at room temperature. Temperature-dependent dielectric response and x-ray diffraction confirm the occurrence of a structural transition in the Pbnm phase at low temperature for the samples with x ≤ 0.4. While the positive magnetodielectric effects can be attributed to a coupling of magnetic and crystallographic structures of the R3c phase, the observed negative magnetodielectric effect in the Pbnm phase can be associated with a low-temperature modification of the Pbnm structure. The observed dual-signed magnetodielectric effects suggest that the Bi1-xGdxFeO3 oxides are a good prototype for understanding the magnetodielectric coupling mechanism in this kind of materials.
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