Journal ArticleDOI
Inductive measurement of ultrafast magnetization dynamics in thin-film Permalloy
TLDR
In this article, an inductive technique for the measurement of dynamical magnetic processes in thin-film materials is described using 50 nm films of Permalloy (Ni81Fe19) and data are presented for impulse and step-response experiments with the applied field pulse oriented in the plane of the film and transverse to the anisotropy axis.Abstract:
An inductive technique for the measurement of dynamical magnetic processes in thin-film materials is described. The technique is demonstrated using 50 nm films of Permalloy (Ni81Fe19). Data are presented for impulse- and step-response experiments with the applied field pulse oriented in the plane of the film and transverse to the anisotropy axis. Rotation times as short as 200 ps and free oscillations of the magnetization after excitation are clearly observed. The oscillation frequency increases as the dc bias field parallel to the anisotropy axis increases as predicted by classical gyromagnetic theory. The data are fitted to the Landau–Lifshitz equation, and damping parameters are determined as a function of dc bias field. Damping for both impulse and step excitations exhibits a strong dependence on bias field. Damping for step excitations is characterized by an anomalous transient damping which rapidly increases at low dc bias field. Transformation of the data to the frequency domain reveals a higher order precessional mode which is also preferentially excited at low dc bias fields. A possible source for both phenomena is precessional mode saturation for large peak rotations. The technique has the potential for 20 ps resolution, although only 120 ps resolution is demonstrated due to the limited bandwidth of the waveguides used.read more
Citations
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Dissertation
Microwave susceptibility of thin ferromagnetic films: metrology and insight into magnetization dynamics
TL;DR: In this article, a vector network analyzer (VNA) ferromagnetic resonance (FMR) was used for the understanding of the magnetization dynamics of model thin film.
Book ChapterDOI
High Speed Switching and Rotational Dynamics in Small Magnetic Thin Film Devices
TL;DR: In this paper, the authors present a review of high-frequency magnetic device measurements and modeling work at NIST which is being conducted to support the development of high speed read sensors, magnetic random access memory, and magnetoelectronic applications.
Journal ArticleDOI
Inductive measurement of the high frequency permeability of a Permalloy thin film
G. Counil,Joo-Von Kim,K. Shigeto,Yoshichika Otani,Thibaut Devolder,Paul Crozat,H. Hurdequint,Claude Chappert +7 more
TL;DR: In this paper, an improved broadband inductive technique for the measurement of magnetization dynamics in thin ferromagnetic films is presented, and demonstrated using 9.3 nm thick Permalloy films, and allows for time and frequency domain measurements to be made in parallel.
Journal ArticleDOI
Direct Current Effects on High-Frequency Properties of Patterned Permalloy Thin Films
TL;DR: In this article, the authors investigated the effect of direct current (dc) on high-frequency properties of two permalloy (Py) submicrometer patterns of 0.24 and 0.55 mum width, 10 nm length, and 100 nm thickness.
Patent
Magnetic materials having superparamagnetic particles
TL;DR: In this article, a magnetic film comprises superparamagnetic particles on at least one surface of the magnetic material and the magnetic film may be patterned and may comprise a ferromagnetic material.
References
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Journal ArticleDOI
A Mechanism of Magnetic Hysteresis in Heterogeneous Alloys
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