Method and system for the individualized characterization of magnetic elements based on ferromagnetic resonance

• US 7,898,251 B2
• Filed: 02/14/2007
• Issued: 03/01/2011
• Est. Priority Date: 02/14/2006
• Status: Active Grant

• Current Assignee: Micromag 2000, S.L.
• Original Assignee: Micromag 2000, S.L.
• Inventors: Hernando Grande, Antonio, Marin Palacios, Pilar, Cortina Blanco, Daniel, Calvo Robledo, Javier
• Primary Examiner(s): Koval; Melissa J
• Assistant Examiner(s): Fetzner; Tiffany A
• Application Number:
  US11/705,723
• Publication Number:
  US 20070187513A1
• Time in Patent Office: 1,476 Days
• Field of Search: 324300-322, 324/244, 174/36, 174/110.R, 174/122.G, 174/94.R, 174/394, 235/435, 340/572.5, 342/1, 600/410, 600/411, 600/422, 315/5.22, 361/146
• US Class Current: 324/300
• CPC Class Codes: G01N 24/10 by using electron paramagnetic resonance G01N24/12 takes precedence
• CPC Class Codes: G01R 33/14 Measuring or plotting hysteresis curves G01R33/1207 takes precedence
• CPC Class Codes: G01R 33/60 using electron paramagnetic resonance G01R33/24, G01R33/62 take precedence
• CPC Class Codes: H01F 1/15391 Elongated structures, e.g. wires

Abstract

A method and system for the characterization of a magnetic element based on ferromagnetic resonance, the magnetic element presents ferromagnetic resonance and its own characteristic resonance frequency. The system includes mechanism for application of a low-frequency electromagnetic field in a given area; a mechanism for application of a high-frequency electromagnetic wave the same as the characteristic resonance frequency of the magnetic element in the same area; and a control unit configured so as to control the simultaneous application of the low-frequency electromagnetic field so that in response to the introduction of the magnetic element in the area the magnetic element absorbs the high-frequency electromagnetic wave with a frequency the same as that of the low-frequency electromagnetic field, so the wave is modulated. The system also comprises a mechanism for reception of this unique individual modulated wave characteristic of each element, and a mechanism for assignment of the unique modulated wave to the element.

Claims

1. A method for the individualized characterization of magnetic elements based on ferromagnetic resonance, wherein each of the magnetic elements exhibits properties of ferromagnetic resonance and each of the magnetic elements has a resonance frequency, the method comprising:

applying in a given area a low-frequency electromagnetic field, wherein the low frequency is between 50-800 Hz;

simultaneously applying in the given area an electromagnetic wave of a high frequency, between 0.5-20 GHz equal to the resonance frequency of a magnetic element;

inserting the magnetic element in the given area in order for the magnetic element to absorb the high-frequency electromagnetic wave with a frequency that is the same as that of the low-frequency electromagnetic field, so the high frequency electromagnetic wave is modulated with a frequency equal to the frequency of the low-frequency electromagnetic field;

receiving a unique and individual modulated wave characteristic of each magnetic element; and

assigning the unique and individual modulated wave characteristic to each magnetic element,

wherein the assignment of the unique and individual modulated wave characteristic to each magnetic element includes modifying a modulated wave by using a low frequency hysteresis loop which characterizes the respective magnetic element.

2. The method according to claim 1, wherein the magnetic element is an amorphous magnetic element.

3. The method according to claim 1, wherein the magnetic element is a magnetic microwire.

4. The method according to claim 1, wherein the method is further implemented for identification of magnetic elements, comprising:

performing an initial characterization on a first magnetic element, thereby obtaining a first unique modulated signal by applying the method of individual characterization;

applying the method of individual characterization to a second magnetic element and obtaining a second unique modulated wave; and

comparing the first and second modulated waves and, if they are the same, identifying the second magnetic element as the first magnetic element.

5. A system for the characterization of magnetic elements based on ferromagnetic resonance, wherein each of the magnetic elements exhibits properties of ferromagnetic resonance and each of the magnetic elements has a resonance frequency, the system comprising:

a means for applying a low-frequency electromagnetic field in a given area, wherein the low frequency is between 50-800 Hz;

a means for applying a high-frequency electromagnetic wave between 0.5 and 20 GHz, which is equal to the resonance frequency of a magnetic element in the given area;

a means for controlling simultaneous application of the low-frequency electromagnetic field and the high-frequency electromagnetic wave, such that in response to the introduction of the magnetic element in the given area, the magnetic element absorbs the high-frequency electromagnetic wave with a frequency that is the same as that of the low-frequency electromagnetic field, so the high-frequency electromagnetic wave is modulated with a frequency equal to the frequency of the low-frequency electromagnetic field;

a means for receiving a unique and individual modulated wave characteristic of each magnetic element, and

a means for assigning the unique and individual modulated wave characteristic to each magnetic element;

wherein the assignment of the unique and individual modulated wave characteristic to each magnetic element includes modifying a modulated wave by using a low frequency hysteresis loop which characterizes the respective magnetic element.

6. The system according to claim 5, where the means for assignment of the unique and individual modulated wave characteristic of the magnetic element to the magnetic element includes a means for encoding the modulated wave.

7. The system according to claim 5, wherein the magnetic element is an amorphous magnetic element.

8. The system according to claim 5, wherein the magnetic element is a magnetic microwire.

9. The system according to claim 5, wherein the system is implemented for identification of magnetic elements, by:

providing an initial characterization on a first magnetic element, thereby obtaining a first unique modulated signal by applying the system of characterization;

applying the system of characterization to obtain a second unique modulated wave of a second magnetic element; and

comparing the first and second modulated waves and, if they are the same, identifying the second magnetic element as the first magnetic element.