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Ferromagnetic Layer (ferromagnetic + layer)

Distribution by Scientific Domains
Physics and Astronomy100%

Selected Abstracts

Microcircuit tailoring in ferromagnetic semiconductor (Ga,Mn)As

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
T. Figielski
Abstract In order to search for novel giant-magnetoresistance systems, we fabricated and investigated narrow constrictions in the layers of the ferromagnetic semiconductor (Ga,Mn)As. We found that constrictions a few hundred nanometers wide, tailored by means of the electron-beam lithography and wet etching, were not conducting at liquid helium temperatures unless illuminated, probably due to the trapping action of surface states appearing on an extra surface area denuded by the etching. To avoid this, we used selective implantation of oxygen ions into the ferromagnetic layer to tailor the constrictions. We have shown that such an implantation inactivates Mn acceptors in the layer and destroys ferromagnetism. We propose an application of oxygen ion implantation as a method of fabricating microcircuits in future spin electronics based on Mn-containing III,V semiconductor compounds. [source]

Spin-wave spectra and magnetization of ferro,ferrimagnetic double layers

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 6 2008
Wei Jiang
Abstract The spin-wave spectra and magnetization of the ferro,ferrimagnetic double layers are studied by using a linear spin-wave approximation and retarded Green's-function method. We obtain the four branches of the spin-wave spectra. Two energy gaps are found to exist in the energy band. The effects of the interlayer exchange coupling, the intralayer exchange coupling and the spin quantum numbers on the spin-wave spectra and the energy gaps are discussed. The minimum (maximum) value point on the spin-wave spectra and energy gaps correspond to a system that has a high symmetrical magnetic structure and the balance of quantum competitions among the exchange couplings and the spin quantum numbers of the system. There is a crossover between sublattice magnetizations in ferromagnetic layer that is affected by quantum fluctuations, thermal fluctuations and frustration of spins. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnetic hysteresis loop in antiferromagnetically coupled bilayer structures

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 4 2008
Yan Ma
Abstract The hysteresis behavior of a bilayer film system, in which a hard ferromagnetic layer with larger anisotropy and spin-3/2 couples with a soft ferromagnetic layer with smaller anisotropy and spin-1 antiferromagnetically, is studied by using the Ising model and the linear cluster approach. We calculate the magnetic reversal of the soft magnetic layer at low field while keeping the saturated magnetization state of the hard magnetic layer unperturbed, and find a phenomenon of exchange bias. The influences of anisotropy, intralayer exchange in the soft magnetic layer, and the interlayer exchange on the coercivity and exchange bias in the bilayer film are discussed. It is found that increasing the interlayer coupling can enhance the exchange bias of the system, and the easy plane anisotropy in soft magnetic layers can induce the hysteresis loop moving towards positive field. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Thickness dependence of magnetic coupling strength and thermal stability in a spin-dependent tunnel junction

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2004
C. H. Nam
Abstract The change of magnetic coupling strength between two ferromagnetic layers, separated by an insulating barrier, was investigated as a function of the barrier thickness (TB) and thermal annealing temperatures. The magnetic junctions consist of Ta/CoFe/AlOx/NiFe/Ta layers with three different nominal thickness of TB = 1.3, 1.6, and 2.0 nm. Isothermal magnetization at room temperature revealed that, while the junction with a lower TB showed a higher magnetic coupling strength, thermal annealing at T = 225 °C increased (and diminished) the coupling strength of the junctions with TB = 1.3 and 1.6 nm (and 2.0 nm), respectively. This observation was utilized to understand consistently the magneto-resistance behavior and specific junction resistance of the junctions as a function of thermal annealing temperature. This study demonstrated that the physical properties of a magnetic tunnel junction, such as magneto-resistance ratio, specific junction resistance and their thermal stability, were substantially influenced by the insulating barrier structure as well as the interface quality between the layers. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Magnetic anisotropy studies on FeNiCo/Ta/FeNiCo three layers film by layer sensitive ferromagnetic resonance technique

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 12 2004
F. Yildiz
Abstract Two ferromagnetic layers that are separated by a non-magnetic spacer have been deposited in the presence of an external Dc magnetic field that has been applied in a mutually perpendicular direction during the deposition of each layer. This thin three-layer film of FeNiCo/Ta/FeNiCo was then studied by electron spin resonance (ESR) technique for different directions of the external magnetic field with respect to the film plane. Beside very anisotropic and strong two main modes, relatively well-resolved and very weak subsidiary peaks in ESR spectra were observed on low field side of the main modes for almost every direction of the external field. The anisotropic behavior as the field is rotated from the film normal towards to the film plane is due to strong demagnetizing field. However, two fold (axial) small anisotropies having 90 degrees phase shifts with respect to the peaks from two different layers were seen to originate from field-induced anisotropy. The small peaks are attributed to magnetostatics modes as well. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Proceedings of the 5th International Conference on Optics of Surfaces and Interfaces (OSI-V)

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2003
Bernardo S. Mendoza
The 5th International Conference on Optics of Surfaces and Interfaces (OSI-V), held in León, Mexico, 26,30 May 2003, brought together researchers and students from universities and institutes who work in different fields of optical spectroscopy. Its goal was the understanding of the potential of the different optical techniques with respect to interface analysis, their present status and their possible limits. Interfaces formed by well understood semiconductors and metals on one side were in the focus of the meeting. Thin layers, rough surfaces, low dimensional structures formed by self-organization through interaction with the substrate, as well as organic and ferromagnetic layers and others structures were of interest as the other interface partner. The scope of the meeting was to bridge the gap between basic and applied science. Apart from recent advances in theoretical modeling and experimental research, special attention was also paid to novel techniques of optical spectroscopy at interfaces. [source]