Magnetic interactions in ferromagnetic manganite nanotubes of different diameters

• Published in: Applied surface science Vol. 254; no. 1; pp. 368 - 370
• Main Authors: Curiale, J., Sánchez, R.D., Troiani, H.E., Leyva, A.G., Levy, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 31.10.2007; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Domain effects, magnetization curves, and hysteresis; Exact sciences and technology; Magnetic interaction; Magnetic properties and materials; Magnetic properties of nanostructures; Magnetization; Magnetization curves, hysteresis, Barkhausen and related effects; Magnetization curves, magnetization reversal, hysteresis, barkhausen and related effects; Magnetotransport phenomena, materials for magnetotransport; Manganite nanotubes; Manganites; Materials for spintronics; Physics; 68.37.Lp; Magnetic interaction; 68.37.Hk; Materials for spintronics; Magnetization; 75.47.Lx; 75.50.Tt; Manganite nanotubes; 75.75.+a; 76.30.−v; Nanotubes; Dipole interactions; Thickness; Nanoparticles; Strontium Manganites; Manganite nanotubes; Magnetic interaction; Magnetization; Materials for spintronics; Remanent magnetization; Magnetic domains; Calcium Manganites; Ferromagnetism; Surface layers; Demagnetization; 75.75.+a; 75.47.Lx; 76.30.-v; 75.47.Lx; 75.50.Tt; 68.37.Lp; 68.37.Hk; Lanthanum Manganites
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2007.07.074

In this work we present a magnetic study of La 0.67Sr 0.33MnO 3 (LSMO) and La 0.67Ca 0.33MnO 3 (LCMO) nanotubes with nominal external diameters ( ϕ) of 100, 200, 600 and 800 nm. The 800 nm diameter nanotubes have walls of around 50 nm thickness in all the cases. The walls are constituted by an assembly of nanoparticles with a non-Gaussian size distribution presenting a maximum at 24 ± 6 nm (LSMO) and 25 ± 8 nm (LCMO). We carried out isothermal remanent magnetization (IRM) and dc demagnetization (DCD) experiments. We determined that the crystallites are single magnetic domains with a magnetic dead layer on the surface which avoids exchange interactions among grains. We conclude that the dominating interactions are of dipolar type of the same magnitude for all the samples.