Impedance Spectroscopy in Ferromagnetic Materials

2001 ◽  
Vol 699 ◽  
Author(s):  
Raul Valenzuela
Keyword(s):  
Impedance Spectroscopy ◽  
Domain Wall ◽  
Ferromagnetic Materials ◽  
Spin Rotation ◽  
Giant Magnetoimpedance ◽  
Wall Displacement ◽  
Amorphous Wires ◽  
Wide Range ◽  
Electric Materials ◽  
Magnetization Processes

AbstractImpedance spectroscopy (IS) is a powerful characterization methodology for a wide range of electric materials such as ceramics, ferroelectrics, ion conductors, piezoelectrics, etc. In this paper, an extension of IS to the case of ferromagnetic materials is presented. In particular, the resolution of the most common magnetization processes (domain wall bulging, domain wall displacement and spin rotation) is analyzed. IS is applied to ferrites and giant magnetoimpedance in amorphous wires.

Impedance Spectroscopy of Ferromagnetic Materials

1995 ◽  
Vol 411 ◽  
Author(s):  
R. Valenzuela ◽  
J. T. S. Irvine
Keyword(s):  
Impedance Spectroscopy ◽  
Domain Wall ◽  
Solid Electrolyte ◽  
Ferromagnetic Materials ◽  
Ferromagnetic Hysteresis ◽  
Polarization Phenomena ◽  
Hysteresis Phenomena

ABSTRACTImpedance spectroscopy has been widely used to analyze polarization phenomena in dielectric, ferroelectric and solid electrolyte materials. In this paper, we review its extension to ferromagnetic materials, and discuss its application to the case of irreversible domain wall displacements which lead to ferromagnetic hysteresis phenomena.

Circumferential permeability in nonmagnetostrictive amorphous wires

1996 ◽  
Vol 11 (10) ◽  
pp. 2486-2489 ◽  
Author(s):  
M. L. Sanchez ◽  
R. Valenzuela ◽  
M. Vazquez ◽  
A. Hernando
Keyword(s):  
Domain Wall ◽  
Current Amplitude ◽  
Complex Permeability ◽  
Equivalent Circuits ◽  
Magnetization Curves ◽  
Frequency Range ◽  
Impedance Response ◽  
Amorphous Wires ◽  
Circular Field ◽  
Magnetization Processes

Real and imaginary components of the impedance response on Co68.1Fe4.4B15Si12.5 amorphous as-cast wires were measured in the 100 Hz-100 kHz frequency range and 0.05–30 mA (RMS) current amplitude, at axial dc fields of 0 and 4800 A/m. From these data, plots of circumferential complex permeability as a function of circular field, as well as magnetization curves, were derived. Results are analyzed in terms equivalent circuits, which allows a resolution of domain wall and rotational contributions to the circumferential magnetization processes.

scholarly journals Harmonic hybrid inflation

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Federico Carta ◽  
Nicole Righi ◽  
Yvette Welling ◽  
Alexander Westphal
Keyword(s):  
Domain Wall ◽  
Symmetry Breaking ◽  
Initial Conditions ◽  
Scalar Potential ◽  
Field Range ◽  
Slow Roll ◽  
Minimal Form ◽  
Wide Range ◽  
Hybrid Inflation ◽  
Type Iib String Theory

Abstract We present a mechanism for realizing hybrid inflation using two axion fields with a purely non-perturbatively generated scalar potential. The structure of the scalar potential is highly constrained by the discrete shift symmetries of the axions. We show that harmonic hybrid inflation generates observationally viable slow-roll inflation for a wide range of initial conditions. This is possible while accommodating certain UV arguments favoring constraints f ≲ MP and ∆ϕ60 ≲ MP on the axion periodicity and slow-roll field range, respectively. We discuss controlled ℤ2-symmetry breaking of the adjacent axion vacua as a means of avoiding cosmological domain wall problems. Including a minimal form of ℤ2-symmetry breaking into the minimally tuned setup leads to a prediction of primordial tensor modes with the tensor-to-scalar ratio in the range 10−4 ≲ r ≲ 0.01, directly accessible to upcoming CMB observations. Finally, we outline several avenues towards realizing harmonic hybrid inflation in type IIB string theory.

Diameter dependence of the giant magnetoimpedance in hard-drawn CoFeSiB amorphous wires

2002 ◽  
Vol 91 (10) ◽  
pp. 7418 ◽  
Author(s):  
Jifan Hu ◽  
Hongwei Qin ◽  
Fuzhong Zhang ◽  
R. K. Zheng
Keyword(s):  
Giant Magnetoimpedance ◽  
Amorphous Wires

Domain wall permeability limit for the giant magnetoimpedance effect

2002 ◽  
Vol 91 (10) ◽  
pp. 7451 ◽  
Author(s):  
J. M. Barandiarán ◽  
A. Garcı́a-Arribas ◽  
J. L. Muñoz ◽  
G. V. Kurlyandskaya ◽  
R. Valenzuela
Keyword(s):  
Domain Wall ◽  
Giant Magnetoimpedance ◽  
Giant Magnetoimpedance Effect ◽  
Wall Permeability

The Noise Generated in a Coil with a Ferromagnetic Core

1954 ◽  
Vol 7 (4) ◽  
pp. 654
Author(s):  
G Builder ◽  
D Haneman
Keyword(s):  
Domain Wall ◽  
External Source ◽  
Irreversible Processes ◽  
Barkhausen Noise ◽  
The Core ◽  
Ferromagnetic Core ◽  
Irreversible Magnetization ◽  
Considerable Detail ◽  
Magnetization Processes ◽  
Magnetizing Field

It is well known that Barkhausen noise will be induced in a coil which has a ferromagnetic core, if the core is subjected to any considerable degree of varying or alternating magnetization due to current flowing in the coil or due to a magnetizing field from some external source. This effect is ascribed to irreversible magnetization processes, such as irreversible domain wall movements, and has been investigated in considerable detail. It has recently been utilized to estimate the amount of the contribution of such irreversible processes to the total magnetization (Tebble, Skidmore, and Corner 1950).

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