Thin Film Fabrication of R 2 Fe 14 B Compounds
- PDF / 442,853 Bytes
- 9 Pages / 420.48 x 639 pts Page_size
- 102 Downloads / 175 Views
THIN FILM FABRICATION OF R2 Fe14 B COMPOUNDS J.F. ZASADZINSKI, C.U. SEGRE, E.D. RIPPERT, J. CHRZAS AND P. RADUSEWICZ Department of Physics, Illinois institute of Technology, hicago, IL 60616
ABSTRACT
Thin 'Yilms (=4000 A) of R2 Fe14 B compounds have been synthesized by d.c. triode sputtering for R=Nd,Sm and Er. Deposition onto single-crystal substrates heated to 600"C and with rates of 1.3 A/s results in nearly epitaxial film growth such that the c-axis of the tetragonal structure is perpendicular to the film plane. As a consequence, intrinsic anisotropy effects are observed in the magnetic properties of the as-made films. Although sapphire and quartz substrates give the best results, similar directed growth is observed on recrystallized Nb foils. Magneto-optical measurements on the Nd-based compounds give a remnant polar Kerr angle or=0.22° and coercive field Hc= 5 . 5 kOe. The easy axis is in the film plane for R=Sm and Er and a remnant magnetization greater than 80% of saturation is observed for H applied parallel to the film plane. Electrical resistivity measurements on Nd2 Fe14 B films indicate that spin-disorder scattering from the rare earth site is important and features from both the Curie and spin reorientation temperatures are observed. INTRODUCTION The discovery of Fe-based permanent magnet materials with energy products greater than 45 MGOe for Nd2 Fe1 4 B and related alloys [1,2] has
spurred a tremendous amount of research into the fabrication of these compounds in bulk and thin film form. Thin film fabrication is a powerful method of materials synthesis which offers a unique way of investigating both the basic and applied aspects of the magnetic compounds, R2 Fe14 B (R=rare earth). Micro-stepper motors [3] and electronic circuits [4] are but a few of the applications in which thin film techniques may be used. The strong anisotropies found in the R2 Fe14 B compounds are a source of fundamental interest and similarly provide some unique magnetic structures. It is well-known that in order to obtain the best magnetic properties, it is important to have small grain size and multi-phase material as well as preferential orientation. Nevertheless, the ability to grow single crystal films epitaxially is of fundamental importance for being able to measure the intrinsic properties of these materials and to better understand the origin of the magnetic interactions which make these materials promising. It is also the first step in fabricating superlattices on this class of compounds. We report that single-phase thin films of R2 Fe14 B compounds can be grown with a high degree of epitaxy such that essentially all of the crystallites are oriented with their c-axis perpendicular to the film plane. This permits investigation of intrinsic properties such as the magnetic anisotropy, the electron scattering and the magnon spectrum. In addition, it is found that, to a reasonable degree, the orientation is maintained for a variety of substrates including sapphire, quartz and Mat. Res- Soc. Symp. Proc. Vol. 96.
1987 Ma
Data Loading...
