Stock material or miscellaneous articles – Composite – Of inorganic material
Patent
1997-10-30
2000-09-12
Resan, Stevan A.
Stock material or miscellaneous articles
Composite
Of inorganic material
205316, 205319, 205479, 205483, H01F 1008
Patent
active
061175684
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a cyanochromium-complex-based magnetic material and a manufacturing method thereof. More particularly, the present invention relates to a cyanochromium-complex-based molecular magnetic material having excellent magnetic properties including a high magnetic transition temperature and permitting electrochemical control of magnetic properties thereof, and a manufacturing method thereof.
2. Background Art
The general attention has recently been attracted by molecular magnetic materials having fundamental skeletons of organic radicals, charge-transfer complex and metal complex, quite different from conventionally known magnetic materials.
In spite of expectation of future progress, study on these molecular magnetic materials has just been started, and almost no efforts of scientific research or technological approach have so far been made on improvement of magnetic properties and control thereof as well as manufacturing methods of such materials.
The present invention was developed in view of these circumstances as described above and has an object to provide a novel molecular magnetic material, expected to have ample potentialities in the future, excellent in magnetic properties, which permits control of these properties, and a manufacturing method thereof.
SUMMARY OF THE INVENTION
As means for solving the foregoing problems, the present invention provides a cyanochromium-complex-based magnetic material formed on an electrode as a thin film through electrochemical reduction of Cr.sup.3+ into Cr.sup.2+ in a solution in which [Cr(CN).sub.6 ].sup.3- and Cr.sup.3+ are present.
The invention further provides a cyanochromium-complex-based magnetic material of which magnetic properties are variable reversibly through electrochemical oxidation and reduction.
The invention further provides a manufacturing method of a cyanochromium-complex-based magnetic material formed on an electrode as a thin film through electrochemical reduction of Cr.sup.3+ into Cr.sup.2+ in a solution in which [Cr(CN).sub.6 ].sup.3- and Cr.sup.3+ are present.
With regard to the manufacturing method, the invention provides embodiments in which magnetic properties are controlled in various manners by altering the electrolytic conditions such as the reduction potential, concentration of the electrolyte, setting of a constant potential and a constant current, quantity of electricity and coexistent ions. For example, in an embodiment, the foregoing solution contains one or more kinds of ions selected from the group of alkali metal ion, alkali earth metal ion, rare earth metal ion and ammonium ion.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a descriptive view of the cyanochromium-complex-based magnetic material of the invention,
FIG. 2 is a graph illustrating the result of measurement of infrared absorption spectrum of a sample A as an embodiment,
FIG. 3 is a graph illustrating the result of measurement of infrared absorption spectrum of a sample B as an embodiment,
FIG. 4 is a graph illustrating the result of measurement of infrared absorption spectrum of a sample C as an embodiment;
FIG. 5 illustrates a crystal structure model of the foregoing sample A.
FIG. 6 is a graph illustrating the result of measurement of temperature dependency of magnetization of the foregoing samples A, B and C;
FIG. 7 is a descriptive view illustrating the reducing action of a sample,
FIG. 8 is a graph illustrating temperature dependency of magnetization before and after reduction of the sample A with a reduction potential of -1.20 V;
FIG. 9 is a graph illustrating temperature dependency of magnetization before and after reduction of the sample B with a reduction potential of -1.20 V;
FIG. 10 is a graph illustrating temperature dependency of magnetization before and after reduction of the sample C with a reduction potential of -1.20 V;
FIG. 11 is a graph illustrating temperature dependency of magnetization before and after reduction of the sample A with a reduction potential of -0.95 V; and
REFERENCES:
Sato et al., "Electrochemically Tunable Magnetic Phase Transition in a High-T.sub.c Chrominum Cyanide Thin Film", Science, vol. 271, pp. 49-51, Jan. 5, 1996.
Sato et al., "Electrochemical Syntheses and Electrochromic Properties of Chromium Cyanide Magnetic Thin Films", Chemistry Letters, pp. 37-38, 1997.
Itaya et al "Electrochemistry of Polynuclear Transistion Metal Cyanides: Prussian Blue and Its Analogs" Acc. Chem. Res. 1986, 19, 162-168.
Mallah et al "High-T.sub.c Molecular Based Magnets: Ferrimagnetic Mixed-Valence Chromium(III)-Chromium(II) Cyanides with T.sub.c at 240 and 190 Kelvin" Science vol. 262 Dec. 3, 1993, 1554-1557.
Fujishima Akira
Hashimoto Kazuhito
Iyoda Tomokazu
Sato Osamu
Kanagawa Academy of Science and Technology
Resan Stevan A.
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