Characterizing the Magneto-optic Properties of Amorphous Rare Earth - Transition Metal Thin Films

1998 ◽  
Vol 517 ◽  
Author(s):  
W. A. Challener
Keyword(s):  
Thin Film ◽  
Rare Earth ◽  
Transition Metal ◽  
Figure Of Merit ◽  
Low Noise ◽  
Optical Recording ◽  
High Coercivity ◽  
Metal Thin Films ◽  
Mo Effect ◽  
Magneto Optic

AbstractThe amorphous rare earth - transition metal (RE-TM) thin film alloys and nanolayered materials exhibit numerous properties advantageous for optical recording, including perpendicular anisotropy, high coercivity and low magnetization at room temperature, low noise, and easily adjustable Curie and compensation points. As a result these materials have been employed in all commercial magneto-optic (MO) media. On the other hand, the MO effect of these materials is relatively small and tends to decrease with decreasing wavelength. It is important to understand the useful limits of these materials in MO media, and to determine if their MO figure of merit can be substantially increased through appropriate doping or nanolayering. In this paper we discuss experimental techniques for measuring MO properties, a theoretical approach for analyzing the data and designing optical thin film stacks, and results for a variety of RE-TM thin film materials.

Thermal conductivity of amorphous rare earth—transition metal thin films for magneto-optic recording

1992 ◽  
Vol 216 (1) ◽  
pp. 181-183 ◽  
Author(s):  
L.J. Shaw-Klein ◽  
T.K. Hatwar ◽  
S.J. Burns ◽  
S.D. Jacobs ◽  
J.C. Lambropoulos
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Rare Earth ◽  
Transition Metal ◽  
Metal Thin Films ◽  
Magneto Optic

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

Anisotropic thermal conductivity of rare earth–transition metal thin films

1992 ◽  
Vol 7 (2) ◽  
pp. 329-334 ◽  
Author(s):  
L.J. Shaw-Klein ◽  
T.K. Hatwar ◽  
S.J. Burns ◽  
S.D. Jacobs ◽  
J.C. Lambropoulos
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Rare Earth ◽  
Transition Metal ◽  
Columnar Microstructure ◽  
Deposition Pressure ◽  
Metal Thin Films ◽  
Anisotropic Thermal Conductivity ◽  
Out Of Plane ◽  
Order Of Magnitude

Thermal conductivity measurements were performed on several amorphous rare earth transition metal thin films of varying microstructure. The thermal conductivity perpendicular to the plane of the film, measured by the thermal comparator method, was compared with the thermal conductivity value measured parallel to the plane of the film. The latter value was obtained by converting electrical conductivity values to thermal conductivity via the Wiedemann–Franz relationship. As expected, the columnar microstructure induced during the sputter deposition of the thin films causes an anisotropy in the thermal conductivity values, with the in-plane values consistently lower than the out-of-plane values. The effect is most pronounced for the more columnar films deposited at higher pressure, for which the in-plane thermal conductivity, 0.3 W/mK, is an order of magnitude lower than the out-of-plane thermal conductivity, 4.3 W/mK. The thermal conductivity out of the plane of the film decreased with increasing deposition pressure, due to the decreasing film density.

Amorphous Transition Metal-Rare Earth Alloy Films for Magneto-Optic Recording

1986 ◽  
Vol 80 ◽  
Author(s):  
Fred E. Luborsky
Keyword(s):  
Rare Earth ◽  
Transition Metal ◽  
Perpendicular Magnetic Anisotropy ◽  
Anisotropy Constant ◽  
Environmental Stability ◽  
Large Temperature ◽  
Kerr Rotation ◽  
Rare Earth Alloy ◽  
History Of ◽  
Magneto Optic

AbstractThis paper reviews the history of the development of films for use in magneto-optic recording. A discussion of why these early attempts with films of MnBi and Europium compounds were abandoned is given. The current work on amorphous transition metal-rare earth alloys is then reviewed. The origins of the necessary perpendicular magnetic anisotropy are discussed. The ideal combination of properties desired are: a high room temperature coercivity, a large temperature coefficient of coercivity, a large perpendicular anisotropy constant, large Ms, thermal and environmental stability, and, depending on whether a reflection or absorption mode of operation will be used, a large Kerr rotation with large reflectivity or a large Faraday rotation with a small specific absorption. These factors, their control, bow they influence the recording performance and the limits on performance of these amorphous films are discussed.

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