Magnetic anisotropies and spin reorientations of R/sub 2/Fe/sub 14/B-type compounds

Journal Article · Sat Nov 15 04:00:00 EST 1986 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.337574· OSTI ID:5164290

Abache, C; Oesterreicher, J

Magnetic anisotropy of R/sub 2/T/sub 14/B (R = rare earth and T = transition metals such as Fe and Co) and partly substituted derivatives thereof are studied over a range of temperatures. The salient features are axial anisotropy for Y/sub 2/Fe/sub 14/B versus planar anisotropy for Y/sub 2/Co/sub 14/B. Only R with negative second-order Stevens' factor (such as Nd) will show axial anisotropy contributions near room temperature. However, even in this case nonaxial contributions compete at cryogenic temperature, leading to a spin reorientation for R = Nd and Ho with T/sup R//sub s/ = 140 and 62 K, respectively, for the Fe-based compounds. The symbol R is used to amplify the point that the spin reorientation is primarily triggered by an internal competition of R in question. The origin of this anisotropy competition is further illuminated by studies on partly R substituted materials, such as (Nd/sub 1-//sub x/R/sub x/)/sub 2/Fe/sub 14/B. Several contributions to the complex situation are considered including: (a) different site contributions (4f, 4g), (b) different order crystal-field terms, such as V/sup 0//sub 2/, V/sup 2//sub 2/, and V/sup 0//sub 4/ on 4f and 4g, (c) relative magnitude of exchange and crystal field, and (d) the trend for smaller R to preferentially occupy the 4f site. Another type of spin reorientation is observed when R and T sublattice anisotropies compete. An example is Er/sub 2/Fe/sub 14/B with T/sup R//sup -//sup T//sub s/ = 326 K. More complex mixed cases are either observed or predicted.

• Research Organization: Department of Chemistry and Center for Magnetic Recording Research, University of California, San Diego, La Jolla, California 92093
• OSTI ID: 5164290
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 60:10; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ANISOTROPY
BORON COMPOUNDS
MAGNETIC PROPERTIES
ORIENTATION
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SPIN ORIENTATION
TRANSITION ELEMENT COMPOUNDS