RESEARCH TO INVESTIGATE THE MICROSTRUCTURE OF THE INTERNAL MAGNETIC FIELD IN SELECTED MAGNETIC MATERIALS

• Main Authors: Becker, Joseph J, Graham, Charles D., Jr, Kasper, John S, Kouvel, James S
• Format: Report
• Language: English
• Subjects: ANISOTROPY; COBALT COMPOUNDS; CRYSTAL STRUCTURE; Crystallography; Electricity and Magnetism; ELECTROLYSIS; EQUATIONS OF STATE; GADOLINIUM; GRAIN STRUCTURES(METALLURGY); HOLMIUM COMPOUNDS; INTERMETALLIC COMPOUNDS; MAGNETIC FIELDS; MAGNETIC MATERIALS; MAGNETIC PROPERTIES; MAGNETS; MICROSTRUCTURE; Miscellaneous Materials; NEUTRON DIFFRACTION; PARTICLE SIZE; RARE EARTH COMPOUNDS; SAMARIUM COMPOUNDS; STABILITY; YTTRIUM COMPOUNDS

Section 1 describes the continuing investigation of intermetallic compounds having high magnetization and large magnetocrystalline anisotropy for possible application as permanent magnet materials. MOST OF THIS WORK HAS BEEN ON COMPOUNDS OF THE TYPE Co5R, where R is yttrium or a rare earth. While grinding may have detrimental effects on permanent magnet properties, a procedure involving electrochemical or chemical particle size reduction is very effective. The compound Co5Sm shows the best permanent magnet properties to date. There appears to be a problem with stability, even at room temperature, with all of these materials. A procedure for separation high from low coercive force material has been devised. An analysis of the angular variation of coercive force has been made and compared with experiment. Section 2 describes attempts at purfication of rare earth metals and alloys by solid-state electrolysis and presents the results of an investigation of the basal plane anisotropy of gadolinium. Neutron diffraction patterns have been obtained on Y2Co17 and Ho2Co17 samples. Their analysis is now under way, as reported in Section 3. Section 4 describes the experimental study of the detailed magnetic behavior of CrO2 near its Curie point and also indicates how all the magnetization-field-temperature data appear to conform to an equation of state of a very special kind. (Author)