A sensor may include a core and a coil. The core may include a rectangular substrate, a layer of magnetically-permeable material disposed on the substrate, and an adhesive rigidly coupling two ends of the substrate so as to form a tube with the rectangular substrate. The coil may be wound on the tube. The core may further include a layer of radiopaque material. The core may further include a flex pad for electrically coupling the coil with an external system.

An object of the present invention is to provide a Magneto-Resistance (MR) element showing a high Magneto-Resistance (MR) ratio and having a suitable Resistance-Area (RA) for device applications. The MR element of the present invention has a laminated structure including a first ferromagnetic layer 16, a non-magnetic layer 18, and a second ferromagnetic layer 20 on a substrate 10, wherein the first ferromagnetic layer 16 includes a Heusler alloy, the second ferromagnetic layer 20 includes a Heusler alloy, the non-magnetic layer 18 includes a I-III-VI.sub.2 chalcopyrite-type compound semiconductor, and the non-magnetic layer 18 has a thickness of 0.5 to 3 nm, and wherein the MR element shows a Magneto-Resistance (MR) change of 40% or more, and has a resistance-area (RA) of 0.1 [Ωμm.sup.2] or more and 3 [Ωμm.sup.2] or less.

The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.

The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.

A sensor may include a core and a coil. The core may include a rectangular substrate, a layer of magnetically-permeable material disposed on the substrate, and an adhesive rigidly coupling two ends of the substrate so as to form a tube with the rectangular substrate. The coil may be wound on the tube. The core may further include a layer of radiopaque material. The core may further include a flex pad for electrically coupling the coil with an external system.

The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.

Methods for forming magnetic tunnel junctions and structures thereof include cryogenic etching the layers defining the magnetic tunnel junction without lateral diffusion of reactive species.

A sensor may include a core and a coil. The core may include a rectangular substrate, a layer of magnetically-permeable material disposed on the substrate, and an adhesive rigidly coupling two ends of the substrate so as to form a tube with the rectangular substrate. The coil may be wound on the tube. The core may further include a layer of radiopaque material. The core may further include a flex pad for electrically coupling the coil with an external system.

A tunnel magnetic resistance element includes the following, a fixed magnetic layer with a fixed direction of magnetization, a free magnetic layer in which the direction of magnetization changes, and an insulating layer which is positioned between the fixed magnetic layer and the free magnetic layer. The fixed magnetic layer, the free magnetic layer, and the insulating layer form a magnetic tunnel junction. A resistance of the insulating layer changes by a tunnel effect according to a difference in an angle between the direction of magnetization of the fixed magnetic layer and the direction of magnetization of the free magnetic layer. The free magnetic layer includes a ferromagnetic layer, a soft magnetic layer, and a magnetic bonding layer placed in between. Material of the magnetic bonding layer include Ru or Ta, and a layer thickness is 1.0 nm to 1.3 nm.

The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared. An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum. A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation. A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature. This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode). The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.