High frequency dielectric properties distribution of BiFeO 3 thin filmusing near-field microwave microscopy

• Published in: Review of scientific instruments 2009-11, Vol.80 (11), p.114701-114701-4
• Main Authors: Zhang, Xiao-Yu, Wang, Xuan-Cong, Xu, Feng, Ma, Yun-Gui, Ong, C. K.
• Format: Article
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.3258201

A near-field scanning microwave microscopy (NSMM) is applied to investigate the local perpendicular dielectric information of single-phase multiferroic BiFeO 3 thin film and single crystal LaAlO 3 material. Our NSMM is composed of a vector network analyzer and a simple open-ended coaxial probe, which is quite different from the commercial probe with a λ / 4 coaxial resonator. The local permittivity is calculated quantitatively according to resonance frequency shift under the quasistatic microwave perturbation theory. We make use of the magnitude of reflection loss S 11 to construct an image reflecting the distribution of dielectric constant of a material. A homogeneous permittivity is observed in LaAlO 3 material and the inhomogeneous permittivity ε = 215 - 250 for BiFeO 3 film is depicted from the change of feedback signal S 11 over an area of 100 × 100   μ m 2 .