RU2457279C1 - METHOD OF PRODUCING AMORPHOUS MAGNETIC Co-P FILMS - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves cleaning a substrate, double sensitisation in tin chloride solution with intermediate treatment in hydrogen peroxide solution, activation in palladium chloride solution, thermal treatment at temperature 150-450°C for 30-40 min, deposition of the amorphous magnetic Co-P film on a nonmagnetic amorphous Ni-P layer with thickness of 20-30 nm while applying a homogeneous magnetic field in the plane of the film, wherein a nonmagnetic amorphous Ni-P layer with thickness of 2.0-6.0 nm is further deposited on the amorphous magnetic Co-P film with subsequent deposition of an identical Co-P film.

EFFECT: invention improves quality of amorphous films owing to reduction of coercitive force H_c.

2 dwg, 1 tbl

Description

The invention relates to the field of chemical deposition of amorphous Co-P magnetic films, for example, on polished glass and can be used in computing in information recording and reading heads, in magnetic field sensors controlled by microwave devices: filters, amplitude phase modulators, etc. d.

Existing methods for producing amorphous magnetic films on glass include the steps of: chemical cleaning, sensitization, activation, and deposition from known solutions using sodium hypophosphite as a reducing agent. To improve the quality of films (adhesion, magnetic and other properties), various types and modes of preliminary chemical and thermal processing of glass, various compositions of solutions with additives of salts of mainly organic acids, etc. are used [Gorbunova KM, Nikiforova AA, Sadakov G.A. and other Physico-chemical foundations of the process of chemical cobaltation. M., Science, 1974, pp. 49-58]. [A.S. USSR, IPC C23C 18/18, No. 1145050, BI No. 10 of 03.15.85].

Known methods, providing good quality films for many properties, do not provide this quality for magnetic properties.

The closest in technical essence and the achieved result to the invention (prototype) is a method for producing amorphous Co-P magnetic films on polished glass, including cleaning the substrate, double sensitization in a solution of tin chloride with intermediate processing in a solution of hydrogen peroxide, activation in a solution of palladium chloride, heat treatment at a temperature of 150-450 ° C for 30-40 minutes, deposition of an amorphous Co-P magnetic film on a non-magnetic amorphous Ni-P sublayer with a thickness of 20-30 nm when uniformly applied in the plane of the film of the magnetic field. [IPC patent C23C 18/18, No. 2306367, BI 26 of 09.20.2007 (prototype)].

However, the prototype method does not provide amorphous anisotropic Co-P films of a sufficiently high quality in terms of coercive force.

The technical result of the invention is to improve the quality of amorphous films, namely the reduction of the coercive force N _with .

The technical result is achieved due to the fact that in the method for producing amorphous Co-P magnetic films, which includes cleaning a glass substrate, double sensitization in a tin chloride solution with intermediate processing in a hydrogen peroxide solution, activation in a palladium chloride solution, heat treatment at a temperature of 150-450 ° C within 30–40 min, deposition of an amorphous Co-P magnetic film on a non-magnetic amorphous Ni-P sublayer with a thickness of 20-30 nm when a uniform magnetic field is applied in the film plane, additionally on an amorphous magnetic C An o-P film is deposited with a non-magnetic amorphous Ni-P layer with a thickness ranging from 2.0 to 6.0 nm, followed by deposition of an identical Co-P film.

The necessity of deposition of the intermediate layer (interlayer) of Ni-P in the thickness range 2.0–6.0 nm is due to the fact that stabilization of the coercive force with a minimum value is observed in this thickness range.

The following describes an example of a specific implementation of the proposed method, accompanied by table 1 and figure 1 and 2.

A non-magnetic Ni-P buffer sublayer of thickness d _{1 is} deposited onto a glass substrate prepared by the prototype method with a size of 10 × 12 mm ² and a thickness of 1.5 mm. Precipitation is carried out from a solution of the composition, g / l: nickel sulfate 7, sodium hypophosphite 10, sodium citrate 25, ammonium chloride 17, ammonia 0.7 ml / l at a temperature of 99 ° C and a pH of 7.5. Then, on a Ni-P buffer sublayer from a solution of the composition, g / l: cobalt sulfate 30, sodium hypophosphite 50, sodium citrate 80, ammonia 30 ml / l at a temperature of 97 ° C and a pH of 9.5, an amorphous Co-P magnetic film is deposited with a thickness d ₂ in a uniform magnetic field of 3 kOe. Then, a non-magnetic amorphous Ni-P layer of thickness d _{3 is} again deposited, followed by deposition of an identical Co-P film of thickness d ₄ .

To determine the dependence of the coercive force on the thickness of the intermediate nonmagnetic layer d ₃ , 11 samples were made in which the value of d ₃ consistently varied from 0 to 36 nm. In this case, the thicknesses of the magnetic Co-P films d ₂ , d ₄ and the buffer sublayer d ₁ Ni-P remained unchanged and amounted to 35, 35, and 30 nm, respectively. This was necessary for an objective comparative assessment of the results of coercive force measurements. The thicknesses of the layers were determined by the deposition time at a known deposition rate of control Ni-P and Co-P samples. To determine the deposition rate, the thicknesses of control samples with a known deposition time were previously determined from X-ray spectral data on an S4 PIONER instrument. The coercive force was measured using a looposcope, the principle of which is based on the induction excitation of a signal with an operating frequency of 50 Hz.

Table 1 shows the thicknesses d ₁ , d ₂ , d ₃ and d ₄ 11 samples and the values of H _c . For better perception, the dependence of H _c on the thickness of the interlayer d ₃ Ni-P is shown graphically in FIG. 1 and hysteresis loops in FIG. 2.

From table 1 and figure 1 it is seen that in the absence of a layer of Ni-P (d ₃ = 0), the coercive force of the Co-P film is 7.5 Oe (sample 1). The absence of a layer indicates that this sample was obtained by the prototype method. The presence of the interlayer and the growth of its thickness to 2 nm leads to a decrease in H _c to a value of 0.69 Oe (sample No. 6). This value of the coercive force remains almost unchanged up to the thickness of the interlayer d ₃ ~ 6 nm. With a further increase in the thickness of the intermediate layer, H _c gradually increases and at d ₃ = 36 nm it amounts to 3.5 Oe (sample No. 11). Figure 2 shows the hysteresis loop of the samples obtained: a) by the prototype method (sample No. 1), b) by the proposed method (sample No. 8).

Thus, the proposed method can significantly reduce (more than an order of magnitude) the value of the coercive force and, therefore, improve the quality of amorphous Co-P films in comparison with films obtained by the prototype method.

This method can be successfully used in the preparation of amorphous Co-P magnetic films not only on polished glass, but also on other materials, for example, polycor, ceramic, quartz.

Table 1 No. of samples
p / p d ₁
Ni-P, nm d ₂
Co-P, nm d ₃
Ni-P, nm d ₄
Co-P, nm Magnetic parameter H _c (E) one 30,0 35.0 0,0 35.0 7.50 2 30,0 35.0 0.3 35.0 7.40 3 30,0 35.0 0.4 35.0 6.5 four 30,0 35.0 0.6 35.0 3.3 5 30,0 35.0 1,0 35.0 2.45 6 30,0 35.0 2.0 35.0 0.69 7 30,0 35.0 3.0 35.0 0.65 8 30,0 35.0 4.0 35.0 0.63 9 30,0 35.0 6.0 35.0 0.66 10 30,0 35.0 12 35.0 2.25 eleven 30,0 35.0 36 35.0 3,50

Claims (1)

A method of producing an amorphous magnetic film, including cleaning the substrate, double sensitization in a tin chloride solution with intermediate treatment in a hydrogen peroxide solution, activation of palladium chloride in a solution, heat treatment at a temperature of 150-450 ° C for 30-40 minutes, deposition of an amorphous magnetic film Co -P on a non-magnetic amorphous Ni-P layer with a thickness of 20-30 nm when a uniform magnetic field is applied in the film plane, characterized in that the non-magnetic amorphous Ni-P t layer is additionally deposited on the amorphous magnetic film Co-P lschinoy from 2.0 to 6.0 nm, followed by deposition of an identical Co-P film.

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