Superparamagnetic resonance of single-domain nanoparticles of LaSrMnO3

Abstract

The microwave absorption of an ensemble of single-domain nanoparticles of La0.7Sr0.3MnO3 is investigated in the temperature range 5–300K. At low temperatures the resonance spectra demonstrate the appreciable increase in linewidth and downward shift of the resonance field which are typical for superparamagnetic resonance. With increasing temperature the line shape changes, and at T>TB (TB∼100K) one observes a narrowing of the resonance curve and saturation of the resonance field. The line shape of an individual nanoparticle is described by the dynamic Landau–Lifshitz equations with damping. Modeling of the magnetic dynamics of the system is based on the assumption of a random distribution of the directions of the magnetic moments and of the thermal fluctuations of the direction of the anisotropy axis of the particles. The theory takes into account the dependence of the value of the resonance field on the linewidth.

Spatial confinement of ferromagnetic resonances in honeycomb antidot lattices

“…Surprisingly, but this feature was ignored in theoretical reports addressing resonance properties of antidot lattices. Incorporating findings for FMR for an ensemble of magnetic nanoparticles [40,41], we kept both the resonant (Larmor) and non-resonant (anti-Larmor) terms in the dynamic susceptibility tensor w ij ðr,oÞ.…”

“…This situation is typical, in particular, for an ensemble of single-domain magnetic nanoparticles (see, e.g., Refs. [40,41]), where the direction of the magnetic moments and anisotropy axes of the individual particles may be randomly distributed. For an antidot structure, a broad distribution of the magnetic moment orientations is also quite typical, especially when the external field is insufficient to saturate the sample.…”

Vertical (La,Sr)MnO3 Nanorods from Track‐Etched Polymers Directly Buffering Substrates

“…Here we present a modified version of using track‐etched polymers directly buffering oxide substrates as a novel methodology to generate assisted assemblies of vertical oxide nanostructures using solution methods. Moreover, we have chosen the mixed‐valence manganese oxide (manganite) phase due to its interesting functional properties and because the electronic, magnetic, and lattice degrees of freedom can be modified to reach new phenomena at the nanoscale 24, 25, 29–34…”

Magnetic resonance studies of mixed chalcospinel CuCr2SxSe4−x (x = 0; 2) and CoxCu1−xCr2S4 (x = 0.1; 0.2) nanocrystals with strong interparticle interactions

“…The magnetic resonance properties of non-interacting or weakly interacting magnetic nanoparticles are currently the subject of intense experimental and theoretical studies (see, e.g. [19][20][21][22]). Earlier we investigated the morphologydependent magnetic resonance of CuCr 2 S 4 nanocubes and nanoclusters [23].…”