Phase structure, dielectric properties, and relaxor behavior of (K{sub 0.5}Na{sub 0.5})NbO{sub 3}-(Ba{sub 0.5}Sr{sub 0.5})TiO{sub 3} lead-free solid solution for high temperature applications

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3153128· OSTI ID:21352261

Hongliang, Du; Wancheng, Zhou; Fa, Luo; Dongmei, Zhu ^[1]; Shaobo, Qu ^[2]; Zhibin, Pei ^[3]

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1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072 (China)
2. Electronic Materials Research Laboratory and Key Laboratory of Educational Ministry, Xi'an Jiaotong University, Xi'an 710049 (China)
3. The College of Science, Air Force Engineering University, Xi'an 710051 (China)

The (1-x)(K{sub 0.5}Na{sub 0.5})NbO{sub 3}-x(Ba{sub 0.5}Sr{sub 0.5})TiO{sub 3} (KNN-BST) solid solution has been synthesized by conventional solid-state sintering in order to search for the new lead-free relaxor ferroelectrics for high temperature applications. The phase structure, dielectric properties, and relaxor behavior of the (1-x)KNN-xBST solid solution are systematically investigated. The phase structure of the (1-x)KNN-xBST solid solution gradually changes from pure perovskite phase with an orthorhombic symmetry to the tetragonal symmetry, then to the pseudocubic phase, and to the cubic phase with increasing addition of BST. The 0.90KNN-0.10BST solid solution shows a broad dielectric peak with permittivity maximum near 2500 and low dielectric loss (<4%) in the temperature range of 100-250 deg. C. The result indicates that this material may have great potential for a variety of high temperature applications. The diffuse phase transition and the temperature of the maximum dielectric permittivity shifting toward higher temperature with increasing frequency, which are two typical characteristics for relaxor ferroelectrics, are observed in the (1-x)KNN-xBST solid solution. The dielectric relaxor behavior obeys a modified Curie-Weiss law and a Vogel-Fulcher relationship. The relaxor nature is attributed to the appearance of polar nanoregions owing to the formation of randon fields including local electric fields and elastic fields. These results confirm that the KNN-based relaxor ferroelectrics can be regarded as an alternative direction for the development of high temperature lead-free relaxor ferroelectrics.

• OSTI ID: 21352261
• Journal Information: Journal of Applied Physics, Vol. 105, Issue 12; Other Information: DOI: 10.1063/1.3153128; (c) 2009 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM COMPOUNDS
CURIE-WEISS LAW
ELASTICITY
ELECTRIC FIELDS
FERROELECTRIC MATERIALS
NIOBATES
ORTHORHOMBIC LATTICES
PERMITTIVITY
PEROVSKITE
PHASE TRANSFORMATIONS
POTASSIUM COMPOUNDS
SINTERING
SODIUM COMPOUNDS
SOLID SOLUTIONS
STRONTIUM COMPOUNDS
TITANATES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
DIELECTRIC MATERIALS
DIELECTRIC PROPERTIES
DISPERSIONS
ELECTRICAL PROPERTIES
FABRICATION
HOMOGENEOUS MIXTURES
MATERIALS
MECHANICAL PROPERTIES
MINERALS
MIXTURES
NIOBIUM COMPOUNDS
OXIDE MINERALS
OXYGEN COMPOUNDS
PEROVSKITES
PHYSICAL PROPERTIES
REFRACTORY METAL COMPOUNDS
SOLUTIONS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS