Eur. Phys. J. B 25, 167-176 (2002)
https://doi.org/10.1140/epjb/e20020019

Structure and magnetic properties of epitaxial cobalt islands

¹ Institut de Physique et de Chimie des Matériaux de Strasbourg, 23 rue du Loess, 67037 Strasbourg Cedex, France
² Laboratoire de Physique des Matériaux (UMR CNRS 7556) , BP 239, 54506 Vandœuvre-lès-Nancy Cedex, France
³ Department of Physics, University of Western Australia, Nedlands, WA 6907, Australia

Corresponding author: ^a hehn@lpm.u-nancy.fr

Received: 24 August 2001
Published online: 15 January 2002

Abstract

Growth, structural and magnetic properties of cobalt island structures grown by molecular beam epitaxy on 4 nm thick island shaped Ru buffers are studied. The islands are characterized by a narrow distribution of sizes, and are separated on average by spacing of around one hundred nanometers. Growth of the islands into continuous films is found to proceed in three well defined stages, and corresponding magnetic behaviors are identified. The particles formed in the first stage of growth appear to be similar in shape and size, and their magnetic behavior suggest the presence of superparamagnetism. Particles in the second stage of growth are ferromagnetic and display a reorientation transition of their magnetization out of the film plane, consistent with that seen in patterned magnetic dot arrays. Particles coalesce in the last stage of growth and magnetic properties of continuous films are observed.