[show abstract][hide abstract] ABSTRACT: We present the application of a scanning microwave microscope technique to biological samples. Since dielectric properties of most biological samples originate mainly from the water they contain, we were able to obtain microscope images of biological samples by our scanning microwave microscope technique. As a model system, we have measured the electrical properties of water in the microwave region. The high dielectric constant and the large loss tangent of water were verified. Furthermore, we have measured the properties of water with differing amounts of sodium chloride concentration ranging from de-ionized water to the saturated solution. We have observed a significant change in the resonant frequency and Q value of the resonator as a function of sodium chloride concentration. The concentration dependence of the signals shows that our scanning microwave microscope technique can be useful for investigating the local electric behavior of biological samples with a simple model of ionic conduction.
[show abstract][hide abstract] ABSTRACT: Using a scanning microwave microscope (SMM), we have investigated the phase separation in a 30% La <sub>5/8</sub> Sr <sub>3/8</sub> Mn O <sub>3</sub> ( LSMO )+70% Lu Mn O <sub>3</sub> ( LMO ) polycrystalline pressed powder sample, in which the LSMO phase is a perovskite ferromagnetic metal while the LMO phase is a hexagonal ferroelectric insulator. When the electrical properties of the sample were imaged using our SMM, the sample showed a significant contrast between the metallic LSMO and the insulating LMO grains, indicating a clear phase separation between the two phases. The metallic phase identified by the SMM clearly showed a ferromagnetic signal when investigated by a magnetic force microscope (MFM), providing solid evidence that the metallic phase is indeed the ferromagnetic LSMO. In addition, we have noticed a slight difference between the images generated by SMM and MFM, and we believe that this is due to the different depth scales probed by the two microscopy techniques.
[show abstract][hide abstract] ABSTRACT: We obtained the electrical images of biological specimens using SMM. SMM investigates local electrical properties of materials in high frequency region ( 1.5 GHz) by detecting the shift of the resonant frequency and the quality factor Q of the resonator. At first, we investigated the NaCl solutions of various concentrations from the de-ionized water to the saturated solution, and observed the drastic change of the resonant frequency and Q depending on the concentration. Since the water was the dominant source of the dielectric signals in biological samples, the change of the resonant frequency and Q of the resonator could be a good reference interpreting various biological samples. We will present various high-frequency electrical images of the biological samples of a plant epidermal cell, and a bone section tissue.
[show abstract][hide abstract] ABSTRACT: We investigated the twin domains of LaAlO3 (001) substrate using a scanning microwave microscope (SMM). Since the SMM can image the local dielectric constant of a sample quantitatively, we can observe the difference of the dielectric constant in the twin domains. Especially the (110) domains were observed more clearly than (100) domains, we attribute this to the difference of the strain in the ferroelastic LaAlO3.
Japanese Journal of Applied Physics 01/2001; 40:6510-6513. · 1.07 Impact Factor