Magnetically Ordered fcc Structure at the Relaxed Grain Boundaries of Pure Nanocrystalline Fe

L. Del Bianco; C. Ballesteros; J. M. Rojo; A. Hernando

doi:10.1103/PhysRevLett.81.4500

Magnetically Ordered fcc Structure at the Relaxed Grain Boundaries of Pure Nanocrystalline Fe

L. Del Bianco, C. Ballesteros, J. M. Rojo, and A. Hernando

Phys. Rev. Lett. 81, 4500 – Published 16 November 1998

Abstract

Pure Fe powders, milled down to 10 nm crystallite size, have been analyzed by a combination of Mössbauer spectroscopy, high resolution transmission electron microscopy, and magnetization measurements. After annealing the as-milled powders at 570 K for 1 hour, a new phase is identified with a hyperfine field of 21 T, a lower magnetic moment than bulk Fe, a magnetic order-disorder transition temperature of about 500 K, and a fcc crystal structure. It is tentatively interpreted as a new magnetically ordered phase of Fe.

Received 6 February 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.4500

Authors & Affiliations

L. Del Bianco^1,*, C. Ballesteros², J. M. Rojo³, and A. Hernando^1,3,†

¹Instituto de Magnetismo Aplicado UCM-Renfe, P.O. Box 155, E-28230 Las Rozas, Madrid, Spain.
²Departamento de Fisica Aplicada, Universidad Carlos III, Madrid, Spain.
³Departamento Física de Materiales, Universidad Complutense, E-28040 Madrid, Spain.

^*On leave from Dipartimento di Fisica, Università di Bologna and INFM, Viale Berti Pichat 6/2, 40126 Bologna, Italy.
^†Author to whom correspondence should be addressed.