Development of fundamental components for amplification of magneto-surface-acoustic-waves in highly magnetostrictive met
- PDF / 227,438 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 24 Downloads / 179 Views
D9.9.1
Development of fundamental components for amplification of magneto-surface-acoustic-waves in highly magnetostrictive metal films by means of electron bunching Takeshi Kawahata, Naohisa Obata, Kazuhiro Nishimura, Hironaga Uchida and Mitsuteru Inoue Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Hibari-Ga-Oka, Tempaku, Toyohashi, Aichi, Japan ABSTRACT In a magneto-surface-acoustic-wave (MSAW) device, phase velocity is controlled by an external magnetic field. We proposed amplification of MSAW with a hybrid structure of FeB amorphous film / InSb semiconductor thin film / LiNbO3 substrate, which is expected to compensate the attenuation of MSAW caused by eddy current loss. In the fabricated MSAW device having the FeB amorphous film with low coercivity and high magnetostrictive, the phase retardation of about 600 degree/cm at magnetic fields of ±300 Oe was obtained. The InSb thin film with a mobility of about 3.5×103 cm2/Vs was obtained by using annealing process. The results show possibility of the MSAW amplification.
INTRODUCTION An Iron-based amorphous film [1] with soft magnetic properties and high magnetostriction, such as Fe80B20 or Fe78Si10B12, is very attractive material for application to a magneto-surface-acoustic-wave (MSAW) device [2] because of large magnetoelastic coupling constant [3]. In previous study, we reported propagation properties of the MSAW device with the Fe80B20 amorphous film on a propagation path of surface-acoustic-wave (SAW) [4]. Because the magnetization of magnetostrictive metal film is tightly coupled to SAW via magnetoelastic interaction, the MSAW device is able to control the phase velocity of SAW continuously by an external magnetic field. It is reported that the MSAW devices were expected to be used as a phase modulator and a magnetic field sensor [5], however, they had a large propagation loss caused by eddy current loss in the magnetostrictive metal film in the region of high driving frequency. On the other hand, when carriers in a semiconductor thin film on the propagation path are accelerated by an external electric field, SAW is amplified by means of electron bunching like the traveling-wave tube [6]. This amplification effect must be applicable to compensate the attenuation of MSAW. In order to accelerate electron in a semiconductor thin film more than SAW velocity (about 4×105 cm/s) by a low electric field, the thin film with large electron mobility would be required. A compound semiconductor InSb could be suitable for the MSAW amplification, because the large electron mobility was obtained by annealing process [7, 8]. Therefore, we proposed that the structure with the Fe80B20 amorphous film / InSb semiconductor thin film / LiNbO3 substrate for the amplification of MSAW [9]. This device is attractive for the realization of the downscale and the high function. In this paper, we describe the MSAW device with the Fe80B20 amorphous thin film on the LiNbO3 substrate. The electron mobility of annealed InSb thin films and propaga
Data Loading...
