We report an inductive method detecting a magnetostrictive resonance signal, which is applied to an ultrasonic magnetostrictive transducer sample. Slab shaped ferrite samples are mounted in a rf coil and actuated by a pulsed rf magnetic field. A dc magnetic field is also applied and the resonance signal from the sample is detected by the same coil after the rf field is turned off. The detector system is identical to a conventional pulse NMR system with quadrature detection. The detected signal is Fourier transformed and wide band spectrum data are obtained. The resonance spectrum data show strong dependencies on the bias dc field strength and direction as well as the dimension of the sample.

We utilize an “inductive pulse” quartz crystal microbalance method to study N2 adsorption on quartz, silver, and a single wall carbon nanotube at 77 K. This method is based on radio frequency electric pulse excitation and ring-down signal measurements of quartz crystal resonators located in an induction coil. The surface areas and adsorption strength c are estimated by the Brunauer-Emmett-Teller (BET) model. The estimated c for quartz and silver surface are about 1/5 times smaller than that measured by the conventional method. This is explained as suppression of the self-heating effect, by using our inductive pulse method. We suggest a simple theoretical estimation of self-heating effects on conventional and inductive pulse methods. For the intermediate adsorption range, we analyze our data using the generalized Frenkel-Hasley-Hill (FHH) model with fractal dimension. While the quartz and silver have fractal dimensions of about 2.2±0.1, single wall carbon nanotube has 1.2±0.1, which are explained by its strong adsorptive force.

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