Magnetic viscosity in a nanocrystaine two phase composite with enhanced remanence

O. V. BILLONI; E. BORDONE; S. E. URRETA; L. M FABIETTI; H. BERTORELLO

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2000 vol. 208 p. 1 - 12

0304-8853

The intrinsic values of the magnetic viscosity and the #uctuation "eld in a two phase composite Nd2Fe14B#0.18 vol.aFe were investigated. The composite studied, with equiaxed and isotropically oriented grains had mean grain sizesfavoring a strong exchange coupling between the phases. The relations between the intrinsic and the experimentallymeasured magnitudes are reviewed and the approximations discussed. For applied "elds close to the coercivity, the timedependence of the magnetization is not well described by a simple logarithmic law. The intrinsic #uctuation "eld is foundto increase when the reverse internal "eld increases in all the ranges investigated and two di!erent regimes are identi"ed.These di!erent regimes are discussed considering the distributions of critical "elds for nucleation of inverse domains inthe hard phase, at hard}soft and hard}hard grain boundaries, respectively