Technology for the Information Readout with Submicron Spatial Resolution PRA-0095

Full TitleThe Development of Technology for the Information Readout with Submicron Spatial Resolution on the Basis of a Fundamentally New Approach Using Non-Uniform Ferromagnetic Resonance Tech Area / Field

INF-SIG: Information and Communications / Sensors and Signal Processing

PHY-SSP: Physics / Solid State Physics

Brief Description of Technology
The operational principle for the information read-out sensors currently under development is based in particular upon the use of the giant magnetoresistive effect. If these sensors, as well as the inductive sensors, are applied to readout information under the superhigh density of data when submicron spatial resolution is required, then serious problems appear because of the low signal level. Our proposed technology differs radically from the traditional method. It is based on the use of non-uniform ferromagnetic resonance (FMR) in a thin film to read out information on the magnetic recording medium with a superhigh density of data [1-3]. Basically, this technology is similar to the NMR tomography. In the case of the NMR tomography, localization of the spin precession range (resolution of the method) is determined by d.c. magnetic field gradient. It is impossible to localize the precession range in this way for the FMR because of the excitation of running spin waves in the magnetic material [3-6]. Nevertheless, the power absorption for the superhigh-frequency field (SHF field) in the non-uniform d.c. magnetic field takes place only in the narrow spatial range, and excited spin waves propagate away from this region. The high-frequency (HF) power absorption depends on the characteristic properties of the magnetic film, as well as the gradient of the applied magnetic field.

Accordingly, it is possible to obtain information on the characteristic properties of the magnetic material as well as on the gradient of the applied magnetic field in the local region. Using this principle, we have developed a new method to read out information on the magnetic recording medium [1-3]. Efficiency of the method has been verified experimentally during the information readout on the magnetic tape with the data density of 200 bit/cm. According to theoretic estimates, it is possible to construct a readout head with a resolution of 0.2 ´ 1.0 micron ´ micron; the expected signal level will be greater by several fold as against the giant magnetoresistance heads being currently under development. The speed of response of this method is 10⁸ bit/s. To construct a head with such resolution, power photolithographic equipment with one-micron resolution is required. Also required is the possibility of growing the epitaxial iron-garnet films with preassigned parameters. Academician S.V.Vonsovsky is involved in the development of this project.

Legal Aspects
An experimental series of date reading has successfully passed the trials at Goskomizobreteniy for method registration of distribution of local magnetic field. A patent for this method has been registered in Russia (No. 1674026 1.05.1991).

Special Facilities in Use and Their Specifications
None.

Scientific Papers
1. Reiderman A.F., Gobov Yu.L., “Novel Method for Detecting Magnetic Fields in the Micron Range of Spatial Periods of Inhomogeneities,” Defektoskopiya, No. 11, pp. 68-71 (1991).

2. Gobov Yu.L., Shmatov G.A., “Method Data Reading Using on Registration of Energy Spin Waves in Ferromagnetic Film in a Nonuniform Magnetic Field,” Pisma v Jornal Thechn. Phys., V.21, No.1, pp. 54-59 (1995).

Дата добавления: 2015-07-20