Research on Rare-Earth Metals and Compounds and Development of Applications Based on Their Magnetic Properties

Abstract

Abstract : The report describes the technical acomplishments achieved during a one year research program on the magnetic and magnetoelastic properties of materials containing elements of the rare-earth series. A primary goal of this program was the development of highly efficient high-frequency ultrasonic transducers based on the extremely high magnetostriction found in most rare- earth materials. Work has been carried out on the propagation of elastic waves in holmium and terbium single crystals, and results have been obtained for the velocity and attenuation of such waves as functions of the temperature and the strength of an applied magnetic field. Single-crystal transducers of gadolinium and terbium have been constructed, and elastic-wave generation in these transducers has been observed, although only preliminary results have been attained. A new theory of magnetic and magnetoelastic effects in the rare earths has been developed, and it promises to shed new light on these phenomena. A facility for the growth of large single crystals of rare-earth materials has been constructed, making possible the study of a wide range of materials. (Author)