FIELD DEPENDENCE OF THE SPIN REORIENTATION TEMPERATURE IN MICRO AND NANOCRYSTALLINE FORMS OF Nd{sub 2}Fe{sub 14}B.

Conference · Sun Aug 18 04:00:00 EDT 2002

OSTI ID:808778

LEWIS, L H ^[1]; HARLAND, C L

---

1. BROOKHAVEN NATIONAL LABORATORY

Insight into the anisotropy behavior of Nd{sub 2}Fe{sub 14}B may be obtained by measurements of the spin reorientation temperature T{sub S} where the overall magnetocrystalline anisotropy changes to allow the magnetic moment to relax from an easy axis to an easy cone configuration. DC magnetization measurements made at various applied fields on sintered and nanocrystalline forms of Nd{sub 2}Fe{sub 14}B indicate a T{sub S} that remains constant for the sintered sample but is strongly field-dependent for the nanocrystalline forms of the material. Specifically, T{sub S} decreases with decreasing applied fields of strengths 5 T, 1 T and 0.01 T. A simple model that minimizes the total energy of the system leads to the conclusion that the spin reorientation temperature is insensitive to applied field. Therefore it is concluded that the apparent decrease in the system's spin reorientation temperatures with decrease in measuring field can be attributed to the nanoscale structure of the system and a difference in the anisotropy constants compared to their bulk values.

• Research Organization: Brookhaven National Lab., Upton, NY (US)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 808778
• Report Number(s): BNL--71066-2003-CP; KC0202020
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
IRON BORIDES
MAGNETIC MOMENTS
MAGNETIZATION
NIOBIUM BORIDES
SPIN ORIENTATION
TEMPERATURE MEASUREMENT