FMR in CoFe/Al2O3 multilayers: from continuous to discontinuous regime

• Type: Article in International Scientific Journal
• Date: 2001

Authors

G.N. Kakazei (Author) Other; pogorelov, y. g. (Author) FCUP; sousa, j. b. (Author) FCUP; Golub, VO (Author) Other; Lesnik, NA (Author) Other; Cardoso, S (Author) Other; Freitas, PP (Author) Other

Journal

Title: Journal of Magnetism and Magnetic Materials

Vol. 226

Pages: 1828-1830

ISSN: 0304-8853

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-000-VPQ

DOI: 10.1016/s0304-8853(00)00867-2

Abstract (EN): Ferromagnetic resonance (FMR) has been studied in CoFe(t)/Al2O3(30 Angstrom) multilayers. With growing nominal thickness t of CoFe layers, transitions from superparamagnetic (SP) to Ferromagnetic (FM) state at t(1) approximate to 13 Angstrom and from granular to continuous structural state at t(2) approximate to 18 Angstrom, previously revealed by magnetotransport studies on this system, are confirmed by the FMR data. The effective anisotropy field H-eff(t) clearly displays three distinct regions: (i) SP at t < t(1), (ii) mixed SP + FM at t(1) < t < t(2), and (iii) FM at t(2) < t. The FMR linewidth DeltaH(t) increases when passing from the continuous to discontinuous regime, mainly due to static fluctuations of internal field on granules. At room temperature DeltaH(t) peaks near t(1), the magnetic percolation point, while at 77 K it still grows below this point, probably due to getting below the AC blocking temperature,

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 3