arXiv subjects

F. Arciprete

Publications and source records attributed to F. Arciprete.

22 records · Page 2Linked to original sources

arXiv2009

Temperature dependent Neel wall dynamics in GaMnAs/GaAs

Extensive Kerr microscopy studies reveal a strongly temperature dependent domain wall dynamics in Hall-bars made from compressively strained GaMnAs. Depending on the temperature magnetic charging of domain walls is observed and nucleation rates depend on the Hall-geometry with respect to the crystal axes. Above a critical temperature where a biaxial-to-uniaxial anisotropy transition occurs a drastic increase of nucleation events is observed. Below this temperature, the nucleation of domains tends to be rather insensitive to temperature. This first spatially resolved study of domain wall dynamics in patterned GaMnAs at variable temperatures has important implications for potential single domain magneto-logic devices made from ferromagnetic semiconductors.

cond-mat.mtrl-sci↗

arXiv2008

Complex domain wall dynamics in compressively strained GaMnAs epilayers

The domain wall induced reversal dynamics in compressively strained GaMnAs was studied employing the magneto-optical Kerr effect and Kerr microscopy. Due to the influence of an uniaxial part in the in-plane magnetic anisotropy (90+/-Delta) domain walls with considerably different dynamic behavior are observed. While the (90+Delta) reversal is identified to be propagation dominated with a small number of domain walls, the case of (90-Delta) reversal includes the nucleation of many domain walls. The domain wall nucleation/propagation energy for both transitions are estimated using model calculations from which we conclude that single domain devices can be achievable using the (90+Delta) mode.

cond-mat.other↗

arXiv2006

Experimental corroboration of the Mulheran-Blackman explanation of the scale invariance in thin film growth: the case of InAs quantum dots on GaAs(001)

Mulheran and Blackman have provided a simple and clear explanation of the scale invariance of the island size distribution at the early stage of film growth [Phil. Mag. Lett. 72, 55 (1995)]. Their theory is centered on the concept of capture zone properly identified by Voronoi cell. Here we substantiate experimentally their theory by studying the scale invariance of InAs quantum dots (QDs) forming on GaAs(001) substrate. In particular, we show that the volume distributions of QDs well overlap the corrisponding experimental distributions of the Voronoi-cell areas. The interplay between the experimental data and the numerical simulations allowed us to determine the spatial correlation length among QDs.

cond-mat.mtrl-sci↗

arXiv2005

How kinetics drives the two- to three-dimensional transition in semiconductor strained heterostructures: the case of InAs/GaAs(001)

The two- to three-dimensional growth transition in the InAs/GaAs(001) heterostructure has been investigated by atomic force microscopy. The kinetics of the density of three dimensional quantum dots evidences two transition thresholds at 1.45 and 1.59 ML of InAs coverage, corresponding to two separate families, small and large. Based on the scaling analysis, such families are characterized by different mechanisms of aggregation, involving the change of the critical nucleus size. Remarkably, the small ones give rise to a wealth of "monomers" through the erosion of the step edges, favoring the explosive nucleation of the large ones.

cond-mat.mtrl-sci↗