KR20210041145A - giant magnetoresistance device - Google Patents

Abstract

The present invention relates to a giant magnetoresistance element in which a substrate, a buffer layer, an antiferromagnetic layer, a fixed layer, a nonmagnetic layer, and a free layer are sequentially stacked. The free layer is formed by sequentially repeatedly stacking a CoFeZr layer/Pd layer twice, and a protective layer formed of SiO_2 is provided on the free layer. According to the giant magnetoresistance element, magnetoresistance ratio characteristics and thermal stability can be improved, and also the advantage of improving resistance to corrosion is provided.

Description

Corrosion inhibiting type giant magnetoresistance device

The present invention relates to a giant magnetoresistive element, and more particularly, to a giant magnetoresistive element having improved magnetoresistive ratio characteristics, thermal stability, and resistance to corrosion.

Magnetoresistance is a phenomenon in which the electrical resistance value changes as the magnetic field applied to the material changes, and a very large change in resistance is observed in the metal concentric lattice (e.g., Fe/Cr) and fine granular alloy thin film (e.g., Cu-Co). The so-called giant magneto-resistance phenomenon was discovered, and using this property, the head and magnetic field sensor, which are information reproducing means, the head material of the ultra-large computer hard disk, the ultra-precise magnetic field sensor, the fixed magnetic field, the recognizer, and the mirror material of the X-ray diffractometer. Application studies in many fields of magnetic fields are being actively conducted.

The giant magnetoresistive element uses a change in resistance due to additional scattering of conductive electrons according to the difference in the spin direction of the free layer and the fixed layer with a conductive nonmagnetic layer interposed therebetween.

Such a giant magnetoresistive element has been disclosed in various ways, such as Korean Patent Publication No. 10-1997-0003289.

On the other hand, the giant magnetoresistive element is constantly required to have a structure capable of improving the magneto-resistance ratio characteristics by improving the thermal stability, structural stability, and magnetization induction in the vertical direction for stably changing the magnetic direction even at high temperatures.

In addition, there is a need for a structure capable of improving resistance to corrosion.

The present invention has been invented to solve the above requirements, and an object thereof is to provide a giant magnetoresistive device having improved magnetoresistive ratio characteristics, thermal stability, and resistance to corrosion.

In order to achieve the above object, the giant magnetoresistive element according to the present invention is a giant magnetoresistive element in which a substrate, a buffer layer, an antiferromagnetic layer, a fixed layer, a nonmagnetic layer, and a free layer are sequentially stacked, the free layer is a CoFeZr layer And a protective layer formed by sequentially stacking the Pd layer twice in order, and formed of SiO _{2 on the free layer.}

In addition, it is preferable _{that any one of Si, SiO 2} , and glass is applied to the substrate, the buffer layer is formed of Nb, and the fixed layer is formed by sequentially stacking a CoFeZr layer/Pd layer/CoFeZr layer.

According to an aspect of the present invention, the antiferromagnetic layer is formed by ion implanting any one of N, Ar, and Xe into CoFeZr.

The giant magnetoresistive device according to the present invention provides an advantage of improving magnetoresistive ratio characteristics, thermal stability, and resistance to corrosion.

1 is a cross-sectional view of a giant magnetoresistive element according to the present invention.

Hereinafter, a giant magnetoresistive element according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a cross-sectional view of a giant magnetoresistive element according to the present invention.

Referring to FIG. 1, a giant magnetoresistive device 100 according to the present invention includes a substrate 110, a buffer layer 120, an antiferromagnetic layer 130, a pinned layer 140, a nonmagnetic layer 150, and a free layer 160. ) And the protective layer 170 are sequentially stacked.

The substrate 110 is formed of any one of Si, SiO _{2, and glass.}

The buffer layer 120 is formed on the substrate 110 and guides growth so that the antiferromagnetic layer 130 can grow smoothly.

The buffer layer 120 may be formed of generally applied Ta.

Alternatively, the buffer layer 120 is formed of an Nb material that supports the synthesis of a superconducting hybrid thin film so as to support the synthesis of a heterogeneous thin film.

The buffer layer 120 is subjected to heat treatment at 250° C. for about 1 hour in a vacuum atmosphere, and in this case, the magnetoresistive property is improved.

The antiferromagnetic layer 130 may be made of an alloy containing Mn.

As an example, the antiferromagnetic layer 130 may be formed of an IrMn alloy, a FeMn alloy, or a NiMn alloy.

Alternatively, the antiferromagnetic layer 130 may be formed by injecting a material having diamagnetic properties into a ferromagnetic layer material for forming the pinned layer 140 to be described later. In this case, the manufacturing process can be simplified.

As an example, the antiferromagnetic layer 130 is formed by ion implanting any one of N, Ar, and Xe into CoFeZr, which is a ferromagnetic material for the fixed layer 140 to be described later.

Here, the antiferromagnetic layer 130 may sufficiently inject any one of N, Ar, and Xe into CoFeZr in an amount capable of maintaining antiferromagnetic properties.

The CoFeZr layer may be formed by sputtering using each of Co, Fe, and Zr base materials.

The pinned layer 140 serves to fix the magnetization direction and is formed to improve thermal stability while improving vertical magnetization.

Here, the degree of perpendicular magnetization refers to having perpendicular magnetic anisotropy with respect to a direction perpendicular to the deposition surface.

Planar magnetic anisotropy, which has magnetic anisotropy in a direction horizontal to the evaporation surface, has an advantage that magnetic anisotropy decreases as the number of thin film stacks increases, whereas perpendicular magnetic anisotropy has the advantage that magnetic anisotropy does not decrease even if the number of thin film layers increases.

The pinned layer 140 is formed by sequentially stacking a CoFeZr layer 141/Pd layer 142/CoFeZr 143 layer.

The CoFeZr layers 141 and 143 are layers formed of a CoFeZr material and provide structural stability such as a nonmagnetic layer 150 and a free layer 160 formed thereon.

That is, the CoFeZr layers 141 and 143 have stable conversion efficiency of a desired magnetization direction even when operating at a high temperature, and are amorphous and have a desired surface precision, so that a multilayer structure formed thereon can be stably grown.

In addition, the Pd layer 142 inserted between the CoFeZr layers 141 and 143 induces perpendicular magnetization of the CoFeZr layers 141 and 143 to improve the magnetoresistive ratio.

In the CoFeZr layers 141 and 143, the fraction (at%) of Zr to CoFe is applied at 15 to 30 at%.

The nonmagnetic layer 150 is formed of Cu or Ag.

The free layer 160 is formed by sequentially stacking the CoFeZr layer/Pd layer twice in sequence.

That is, the free layer 160 is formed of a CoFeZr layer 161 / Pd layer 162 / CoFeZr layer 163 / Pd layer 164.

The free layer 160 provides thermal stability and structural stability by the CoFeZr layers 161 and 163 and also improves vertical magnetization by the Pd layers 162 and 164.

The protective layer 170 is formed on the uppermost Pd layer 164.

The protective layer 170 is formed of _{SiO 2} on the free layer 160 to improve resistance to corrosion.

According to such a giant magnetoresistive element, it provides an advantage of improving resistance to corrosion while improving magnetoresistive ratio characteristics and thermal stability.

110: substrate 120: buffer layer
130: antiferromagnetic layer 140: fixed layer
150: non-magnetic layer 160: free layer
170: protective layer

Claims (3)

In a giant magnetoresistive device in which a substrate, a buffer layer, an antiferromagnetic layer, a fixed layer, a nonmagnetic layer, and a free layer are sequentially stacked,
The free layer is formed by stacking a CoFeZr layer/Pd layer sequentially and repeatedly two times,
A giant magnetoresistive device comprising: a protective layer formed _{of SiO 2} on the free layer. The method of claim 1, wherein the substrate is made _{of any one of Si, SiO 2} , and glass, the buffer layer is formed of Nb, and the fixed layer is formed by sequentially stacking a CoFeZr layer/Pd layer/CoFeZr layer. A giant magnetoresistive element. The giant magnetoresistive device of claim 2, wherein the antiferromagnetic layer is formed by ion implanting any one of N, Ar, and Xe into CoFeZr.

Images