Magnetic Anisotropy Of Films Research Articles

Irradiation Effect of Ion Beam in FexN Films Prepared by IRD

Magnetic thin films of Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> N were prepared by so-called "ion reacting deposition." To clarify the effect of ion beam irradiation during deposition, the difference between use of N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ions and Ar ions was studied. A low-energy broad-beam ion source (Kaufman type) was directed normal to the substrate, which was set obliquely to the direction of iron vapor incidence. All of the Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> N films consisted mainly of paramagnetic ε-Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-3</sub> N and α-Fe according to Mossbauer measurements; that is, separation into two phases took place in these films. The coercive force H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> of iron films prepared by Ar ion beam irradiation decreased with increasing ion current density, while that of Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> N films increased to saturation. This indicates that the ion bombardment did not lead to the increase in H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> . We were able to analyze the film magnetic anisotropy into two different shape anisotropies related to the columnar microstructure of the film. The change in H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> and shape anisotropy in Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> N films can be attributed to the anisotropy in the packing density of α-Fe, as estimated from the observed saturation magnetization of the films.

Magnetic Anisotropy of FeAlSi Sputtered Films

ABSTRACTThe FeAlSi film magnetic anisotropy has been studied in relation to the residual stress and crystalline orientation. Experiments show that the magnetic anisotropy behavior depends on the geometrical location of the substrate with the target during the deposition. The main origin of the magnetic anisotropy is attributable to the magnetoelastic effect due to the residual stress anisotropy, which may be induced by the anisotropic incidence of sputtered particles to the substrate.

Magnetic and Magneto-Optical Properties of Pd/Co Multilayered Films

The magnetic and magneto-optical properties of Pd/Co multilayered films prepared by rf sputtering have been investigated. The perpendicular magnetic anisotropy of films increases as the layering period ? and Co content are decreased. The maximum value obtained for the anisotropy K? was 3.8 × 106 erg/cc, where ? and the Co content were 11 A and 28 at% respectively. The saturation magnetization increases as ? decreases, approaching the same value as for the alloys. The Kerr spectra of multilayered films and of alloy films are alike in having a peak near the wavelength of 400 nm, and they are almost the same when ? ≪ 15 A. These results suggest that the perpendicular anisotropy results from compositionally modulated structures with interfacial alloying rather than wdth sharp bilayer interfaces.

Hall effect in a RE-TM perpendicular magnetic anisotropy film under pulsed high magnetic fields

We measured the Hall loop of an amorphous GdFe film with perpendicular magnetic anistropy under a pulsed high magnetic field. We observed a very interesting behavior of the Hall loop which was considered to be related to a spin-flopping phenomenon.

A new swept-frequency permeameter for measuring the complex permeability of thin magnetic films

A permeameter is described that measures the complex permeability of anisotropic thin magnetic films over a continuous frequency spectrum. The system resolves the permeability into both real and imaginary parts, or magnitude and phase. The frequency span of the permeameters, 0.1-200 MHz, is larger than that of previously reported permeameters. The system has a measurement error of approximately 1%, which for the samples used here corresponds to a low-level permeance detection limit of about 1 mu m, an order of magnitude below the previously reported low level limit of 13 mu m. The system is both compact in size and convenient to use, with measurements taken over the whole frequency range in less than a minute. >

Correlation between Magnetic Properties and Composition of Electroless-Plated Cobalt Alloy Films for Perpendicular Magnetic Recording Media

The magnetic properties of a perpendicular magnetic anisotropy film prepared by an electroless plating method was investigated, from viewpoints of film composition. The value of saturation magnetization, Ms, of the film decreases (9.4 emu cm-3, 30.8 emu cm-3 and 27.0 emu cm-3) by one atomic percentage codeposition of nickel, rhenium and phosphorus, respectively. The codepositions of nickel and phosphorus decrease the value of the perpendicular anisotropically magnetic field, Hk. Simultaneously, however, for the low-cobalt-content region with high Ni content, the codeposition of rhenium increases Hk while decreasing Ms, making it possible to prepare perpendicular anisotropicallymagnetic films. Therefore, in the electroless plating method, lower Ms conditions with high Ni content is advantageous for making perpendicular anisotropically magnetic films.

Magnetic polaritons in an anisotropic film on a ferromagnetic substrate

Substituted rare-earth iron garnet thin films grown by liquid-phase epitaxy on rare-earth iron garnet and exhibiting low saturation magnetization with a uniaxial magnetic anisotropy in a direction perpendicular to the film surface have recently been reported. We have obtained the dispersion relations of surface and guided magnetic polaritons in the film-substrate composite system in the Voigt geometry including retardation effect. Two windows were obtained for the magnetic polariton modes, one corresponding to a surface mode and the other to a guided mode in the anisotropic magnetic film. For low value of the external magnetic field, the frequency of the guided mode moves down with increasing magnetic field while the frequency of the surface mode moves up. For a suitable choice of physical parameters now available in substituted iron garnet films, we predict a crossover of these two branches.

Preparation and Characteristics of Co-Cr Films by EP Magnetron Co-sputtering Technique

Experimental results are given on high-rate low-temperature deposition of Co-Cr films using an exposed pole (EP) magnetron simultaneous sputtering system developed by the authors for deposition of ferromagnetic binary alloy films. A composite target is prepared consisting of a Co washer, a Cr cylinder, and a Co disk; the performance of the sputtering system is examined and the film quality evaluated. The results are as follows: 1) the maximum deposition rate was as high as 0.18 μm/min for 7.6 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of input power; 2) the deposition rate was higher for lower sputtering gas pressures; 3) the substrate temperature was as low as 100°C for 7.6 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> input power; 4) the C-axis of the deposited Co-Cr films was oriented perpendicular to the film plane, with Δθ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</sub> = 8 to 13°; and 5) perpendicular magnetic anisotropy films were obtained when the film M <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> = 300 to 800 emu/cc and H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> = 250 to 350 Oe. Thus it is concluded that EP magnetron simultaneous sputtering is very useful for the deposition of Co-Cr films.

High density magnetic recording system with perpendicular magnetic anisotropy film.

High density magnetic recording system with perpendicular magnetic anisotropy film.

ＥＰマグネトロンスパッタ法によるＣｏ‐Ｃｒ膜の作成と特性

This paper is concerned with the experimental results of the high rate and low temperature deposition of Co-Cr films using an exposed pole (EP) magnetron co-sputtering system developed by the authors for deposition of ferromagnetic binary alloy films. In this paper we prepare a composite target constructed of a Co washer, a Cr cylinder and a Co disk, and examine the performance of the sputtering system and evaluate the film quality. Results : 1) Maximum deposition rate was as high as 0.18 μm/min for 7.6 W/cm2 input power. 2) The deposition rate was higher for lower sputtered gas pressure. 3) The substrate temperature was as low as 100°C for 7.6 W/cm2 input power. 4) The C-axis of the deposited Co-Cr films were in the perpendicular direction to the film plane and Δθ50=8-13°.5) Perpendicular magnetic anisotropy films were obtained for the films of Ms=300-800 emu/cc and Hc=250-350 Oe. Thus, it is concluded that EP magnetron co-sputtering is very effective for the deposition of Co-Cr films.

Measurement of Magnetoelastic Effect for Isotropic Thick Alloy Films

While there are numerous reports on the magnetoelastic (magnetostrictive) effect in uniaxially anisotropic soft magnetic films, no such studies have been reported for isotropic films. A strain gauge and B-H meter were used to determine the anisotropy fields ΔH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sub> induced by uniaxial strain e in an isotropic Fe-Si-Al film, and from this found the strain sensitivity η. The value of η thus determined was far smaller than the strain sensitivity for the bulk material. The discrepancy may be explained by the application of a model for anisotropic samples to isotropic films, or to a small reverse magnetostriction effect.

Complete Magnetic Anisotropy Films for Perpendicular Recording Prepared by an Electroless Plating Method

Abstract A complete magnetic anisotropy film was formed by an electroless plating method for a high-density perpendicular recording medium. The Co alloy plating bath, using ammoniacal malonate–tartrate–succinate mixed complexing agents was studied mainly by varying three main metal ion factors in the bath: i.e., the concentrations of NiSO4, NH4ReO4, and MnSO4. The fine columnar structure of magnetic film in a cross section was confirmed by SEM observation. Three different kinds of eight-inch disks A, B, and C, were prepared under selected conditions with magnetic film thickness of 0.50, 0.25, and 0.20 μm respectively. The recording performance was evaluated with a Winchester ring head with a 0.33 μm gap length under various head-medium spacings. A perpendicular recording mode was confirmed, and the following recording densities were obtained: D50=54 and 58 kFRPI for disk A, and 57 and 63 kFRPI for disk B when using 0.20 and 0.15 μm practical usable spacing respectively, and D50=68 kFRPI for disk C when using the more advanced 0.12 μm spacing. It was suggested that the electroless cobalt alloy plating has a high potential as a process for producing perpendicular recording media.

垂直磁気異方性コバルト合金薄膜作製のための無電解めっき浴における錯化剤の役割

The role of complexing agents in electroless plating baths on the properties of Co alloy films was studied with a view to obtain perpendicular magnetic anisotropy films. The increase in malonate concentration resulted in an increase in saturation magnetization, Ms. The perpendicular anisotropy energy, Ku, reached maximum at 0.6mol dm-3 malonate, while the half-breadth of the rocking curve for hcpCo (002) plane, ΔΘ50, reached minimum at 0.3mol dm-3. An increase in tartrate concentration sharply decreased the Ms value and at low additive concentrations increased the Ku value abruptly from negative to positive. The maximum Ku and minimum ΔΘ50 were obtained at 0.2mol dm-3 tartrate. The succinate improved only the ΔΘ50, reaching a minimum at 0.3mol dm-3 succinate. The above effects of the complexing agents on magnetic properties were explained by changes in the composition of the films, and the merits of mixed complexing agents in the plating bath were discussed on the basis of the results obtained.

無電解めっき型垂直磁化膜におけるレニウム添加の効果

無電解めっき型垂直磁化膜におけるレニウム添加の効果

A new method for analysis of magnetic anisotropy in films using the spontaneous hall effect

A new method to determine the easy axis of films with uniaxial magnetic anisotropy using the spontaneous Hall effect is presented. The principle of the method is explained and its validity is verified by the experiments.

Magnetization reversal in thin magnetic films with perpendicular anisotropy

A one-dimensional theory of magnetization reversal in thin, perpendicularly anisotropic magnetic films is presented. It is postulated that the presence of a defective point creates an infinitely deep, infinitely narrow potential well which inhibits the rotation of local magnetization. The interval D between neighboring defects, the saturation magnetization Ms, the anisotropy constant Ku, and the exchange energy constant A are assumed to be finite and uniform across the film. Starting with an initial state where the film is uniformly magnetized to saturation in the easy direction, we show that a discontinuous change of state occurs when the reverse external field H reaches a critical value Hc. The domains thus nucleated at the critical field expand to cover the entire area of the film as H increases beyond Hc. Using the normalized values of H and D, defined, respectively, as h = H/(2Ku/Ms) and d = D/(4A/Ku)1/2, we show that the critical field hc is a function only of d and that its value decreases significantly as d increases.

ホール効果を用いた一軸磁気異方性膜の磁化容易軸決定法

This paper proposes a new method to determine the direction of easy axis in a uniaxial magnetic anisotropy film using the extraordinary (or spontaneous) Hall effect. In this method, the magnetic easy axis is derived mathematically from two magnetic hard directions. The hard directions are obtained experimentally as the magnetic field directions where the Hall characteristic curve loses hysteresis. In order to examine the validity of the method, nickel thin films with oblique magnetic anisotropy were prepared by oblique incidence evaporation, and the Hall effect was investigated on these films, stressing on the field direction dependence of the Hall curve. The experimental results agreed well with the theoretical considerations. It was also found that the hysteresis disappearance was very sensitive to the direction of the applied field H particularly in magnetically well-oriented films. This fact suggests that the Hall method enables high accuracy measurement of the easy axis. Accuracy better than 0.1° may be expected by this method.

Magnetic thin film inductors for integrated circuit applications

It is extremely difficult to fabricate small air-core inductors of sufficiently high inductance and Q for integrated-circuit applications due to the large number of turns required. Although the need for passive inductors can be circumvented by means of active filters at lower frequencies, such substitutes are difficult to realize at frequencies above 100 MHz. To drastically reduce the number of turns required thus rendering the fabrication of IC inductors feasible, we used anisotropic magnetic film cores of permeability as high as 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> . In this paper, the design and fabrication of such inductors are discussed along with experimental results on their inductance.

Applications of plated wire to the military and space environments

Plated wire is steadily emerging as the preferred storage element for military and space memory applications. Not only are cost and performance improvements extending the regions of application, but reliability conscious military and space programs are adopting this type of memory. This is evidenced by the advent of hardened plated-wire memories for Poseidon and Minuteman missile programs. A prime reason for the attractiveness of plated wire for these applications is its ideal property of true nondestructive readout (NDRO) operation, in which the stored word is retained in the storage medium during all portions of the read cycle. This is made possible by the production of a uniaxial anisotropic closed-flux magnetic film during the plating process.

Effect of Average Stress in Films on Uniaxial Magnetic Anisotropy in Electrodeposited Nickel-Iron Thin Films

To study the effect of average stress in films on uniaxial magnetic anisotropy in nickel-iron thin films electrodeposited on a surface scratched in one direction, measurements of average stress σ, uniaxial magnetic anisotropy constant Ku, magnetization Is, film thickness and weight of films were carried out on films of various composition covering a range from 50% nickel to 100% nickel. These measurements were also carried out on films prepared from a plating bath containing 0.8 g/liter of saccharin. The measured values of σ were found to depend on the composition of films and on saccharin in the plating bath, and the effect of σ on Ku is found to be well explained by the expression Ku=1/2(Nt-Np)Is2+3/2λσsin 2θ.