Disordered Magnetism at the Grain Boundary of Pure Nanocrystalline Iron

E. Bonetti; L. Del Bianco; D. Fiorani; D. Rinaldi; R. Caciuffo; A. Hernando

doi:10.1103/PhysRevLett.83.2829

Disordered Magnetism at the Grain Boundary of Pure Nanocrystalline Iron

E. Bonetti, L. Del Bianco, D. Fiorani, D. Rinaldi, R. Caciuffo, and A. Hernando

Phys. Rev. Lett. 83, 2829 – Published 4 October 1999

Abstract

The low-temperature magnetic behavior of ball-milled nanocrystalline Fe is reported. The results of dc and ac susceptibility, remanence, and magnetic relaxation measurements indicate a transition from a high-temperature ferromagnetic state to a low-temperature disordered regime, where a collective freezing of the crystallites magnetic moments occurs. It is proposed that the behavior is determined by the presence of the structurally disordered grain boundaries, showing spin-glass-like properties.

Received 1 July 1999

DOI:https://doi.org/10.1103/PhysRevLett.83.2829

Authors & Affiliations

E. Bonetti¹, L. Del Bianco^1,*, D. Fiorani², D. Rinaldi³, R. Caciuffo³, and A. Hernando⁴

¹Istituto Nazionale per la Fisica della Materia and Dipartimento di Fisica, Università di Bologna, I-40127 Bologna, Italy
²Istituto di Chimica dei Materiali-CNR, C.P. 10, 00016 Monterotondo Stazione (Roma), Italy
³Istituto Nazionale per la Fisica della Materia and Dipartimento di Scienze dei Materiali e della Terra, Università di Ancona, I-60131 Ancona, Italy
⁴Instituto de Magnetismo Aplicado UCM-Renfe, P.O. Box 155, E-28230 Las Rozas, Madrid, Spain

^*Corresponding author.Present address: Dipartimento di Fisica, Università di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy.Email address: delbianco@df.unibo.it