Exchange bias, training effect, and bimodal distribution of blocking temperatures in electrodeposited core-shell nanotubes

• Type: Article in International Scientific Journal
• Date: 2013

Authors

proenca, m. p. (Author) FCUP; ventura, j. (Author) FCUP; sousa, c. t. (Author) Other; vazquez, m. (Author) Other; araujo, j. p. (Author) FCUP

Journal

Title: Physical Review B - Condensed Matter and Materials Physics

Vol. 87

ISSN: 1098-0121

Publisher: American Physical Society

Indexing

ISI Web of Knowledge - 44 Citations

Scopus - 45 Citations

Other information

Authenticus ID: P-005-1NF

DOI: 10.1103/physrevb.87.134404

Abstract (EN): Co nanotubes (NTs) were electrodeposited inside nanoporous alumina templates by a potentiostatic method and then left in air for the natural oxidation of their inner walls. Temperature-dependent magnetic measurements evidenced the existence of exchange-bias (EB) coupling between the Co ferromagnetic (FM) outer wall and the CoO antiferromagnetic (AFM) inner wall of the NTs. The values of the EB field measured at 6 K were found in the same order of magnitude as those already reported for Co/CoO bilayer thin films and core-shell nanoparticles. The effect of temperature and cooling field on the EB effect between the Co/CoO walls of the NTs is here reported. The training effect of the EB in the Co/CoO NT arrays, measured at 6 K, suggests the existence of a stronger coupling between the AFM and the FM layers that are shaped into a core-shell nanotubular structure, when compared with flat interfaces. A bimodal distribution of blocking temperatures is also found when applying the magnetic field parallel and perpendicular to the NTs' axis. DOI: 10.1103/PhysRevB.87.134404

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7