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To reduce transmission of carbapenemase-producing carbapenem-resistant Enterobacterales (CP-CRE), screening is recommended for patients sharing rooms with CP-CRE-detected patients and healthcare workers caring for them.The aim of this study was to investigate the transmission rate of CP-CRE among exposed people in a tertiary hospital using whole-genome sequencing.This study was conducted in a 1751-bed tertiary teaching hospital from January 2017 to December 2019. Index patients were defined as those with positive results in CP-CRE tests during hospitalization. When an index patient was detected in a shared room, we performed CRE screening tests for patients whose stay overlapped with an index patient's stay for at least one day. Where a second case was found, healthcare worker contacts were also screened. CP-CRE were confirmed, and the carbapenemase type identified, by PCR. Whole-genome sequencing was used to compare isolates from index and exposed patients.During the study period, 47 index patients were identified, and they had been in contact with 152 patients in shared rooms and 54 healthcare workers. None of the healthcare workers had CRE. Among the 152 exposed patients, four patients had the same type of carbapenemases as their CP-CRE index patients and all of them were KPC. Whole-genome sequencing revealed that three of these four pairs showed genotypic accordance between the index and the exposed.The CP-CRE transmission rate among the exposed patients was calculated as 2.0% (= 3/152).

The energy received by solar collectors for power generation is limited to various conditions. The average data on solar irradiation are normally used to determine the potential of solar energy at any location. However, the variation of solar energy due to seasonal differences could affect the actual performance of the collectors, consequently leading to poorly justified system installations, which are high in cost. In this work, the characteristics of solar energy radiation in Kuwait were studied by measuring irradiance and comparing the data of selected time periods in two extreme seasons. A pyranometer, mounted two meters above the ground on a tubular beam in a shade-free area at a solar energy laboratory in Kuwait was used to measure irradiance on three consecutive days in summer and winter. The radiation data were recorded at five-minute intervals in each season for comparison. It was found that the average irradiance energy in the winter was up to 61% less than in the summer. In addition, the study revealed that the day-to-day variation of irradiance in winter (31%) was approximately 6.5 times higher than in the summer (4.8%). Clearly, the operation of solar power generation systems in the area during winter would face significant day-to-day fluctuations. As a result, this would necessitate frequent operation of backup power systems in order to meet the electrical power load demand.

Background: Diazoxide, pharmacological openers of mitochondrial ATP-sensitive potassium channels have been shown to induce early pre-conditioning in the spinal cord. Here, the authors investigated whether diazoxide also induce delayed pre-conditioning and thereby reduce neurologic complications using a rabbit model of spinal cord ischemia. Methods: Infrarenal blood flow was interrupted for 20 min in 21 rabbits. Non-treated control animals received no pre-treatment. Diazoxide (5 mg/kg) were given 48 h before 20 min ischemia in the 48-h DZ group, whereas 15-min DZ group received diazoxide (5 mg/kg) 15 min before 20-min ischemia. Neurological functions were evaluated using Johnson scores for 3 days after reperfusion, after which, spinal cords were procured for hematoxylin and eosin staining for cell counting. Results: Johnson scores revealed a marked improvement in both the diazoxide-treated groups vs. the non-treated control group at 3, 24, 48, and 72 h after reperfusion (P

Adjacent or far track erasure (ATE or FTE) in PMR recording can limit the recording track density. In a typical PMR head design, a shield is added near to the write pole to increase the write field gradient. The shield, however, leads to an additional flux path during writing, resulting in the erasure of neighboring tracks and bit error rate (BER) degradation. The media soft underlayer (SUL) is a part of the flux return path and its magnetic properties can also affect the ATE performance [1]. In this study, we report on systematic experimental and modelling results of ATE and FTE behavior of a PMR head with a wrapped-around shield (WAS) as a function of the SUL permeability and thickness.

A systematic investigation of the structural, magnetic, and recording properties of CoPtCrO media with different intergranular exchange coupling and anisotropy orientation dispersion is performed. Reduced exchange coupling between grains results in lower media transition jitter and nonlinear transition shift. By narrowing the Co anisotropy orientation dispersion, a substantial reduction of both transition and DC noise is achieved. Media with high squareness, coercivity, nucleation field, low exchange and narrow Co c-axis dispersion have been fabricated. Such media exhibit excellent recording performance and are promising for high-density perpendicular recording.

The effect of magnetic "preconditioning" on the recording performance of perpendicular media is investigated. Furthermore, the dependence of the magnetic write width (MWW) of shielded-pole heads (SPH) on soft-underlayer (SUL) type and thickness (t/sub SUL/) and the recording performance of perpendicular media with thin SULs are examined. The MWW dependence on SUL structure is influenced by the pole-to-trailing shield spacing. For a wide-gap (/spl sim/80 nm) SPH, thick single-layer, SULs are preferred. For a narrow-gap (/spl sim/50 nm) SPH, MWW is less sensitive to the SUL type. For both narrow and wide-gap SPH and for media with an antiferromagnetically-coupled SUL, MWW is reduced for t/sub SUL/

A recording density of 130 Gb/in/sup 2/ was achieved using thermally stable conventional CoCrPtB longitudinal media. The high in-plane orientation ratio (OR) of the media resulted in an excellent recording performance due to a narrow switching field distribution as well as a high thermal stability caused by narrow energy barrier distribution. The low noise is attributed to the fully isolated fine grains with a narrow size distribution. A good in-plane c axis crystallographic texture was achieved by using an optimum multilayered structure of underlayer and magnetic layers. A detailed study of high OR media is reported by characterizing the magnetic, microstructural, and read/write properties.

TU Electric has developed and obtained U.S. Nuclear Regulatory Commission (NRC) approval of the methodologies required to support core reload safety analyses. The Electric Power Research Institute-sponsored computer codes RETRAN-02 and VIPRE-01 are used in the non-loss-of-coolant-accident thermal-hydraulic analyses. These methods were employed to support the loading of the core of the Comanche Peak Steam Electric Station, Unit I (CPSES-1), Cycle 5. An overview of the reload safety analysis development effort is provided, with the focus on the qualification of the system transient analysis methodologies. Interactions with the NRC are described. Included is a discussion of the types of questions asked by the NRC and the corresponding TU Electric responses. Comparisons ofcalculated results to actual plant data which demonstrate the validity of the CPSES plant model, are provided. The importance of performing good benchmark comparisons is addressed as it relates to the demonstration of technical competence in the use and interpretation of RETRAN. The effectiveness of the approach used by TU Electric to obtain NRC approval of the reload safety analysis methodology is examined in retrospect. Finally, an assessment is made of the benefits, tangible and intangible, derived from having an in-house reload safety analysis capability.

Magnetic patterns on perpendicular recording media were imaged by spin-stand level dynamic read-back microscopy. High-density tracks are clearly resolved up to 1000 kfci and details of magnetic bit structure, not usually observable using standard read-write tests, are readily observed. Encroachment of tracks on Co-Cr-Pt-O media with low oxygen content and low-coercivity results in a nonuniform erasure; as-written rectangular bits become trapezoidal in shape. Media with high oxygen content and high coercivity provide superior side erasure resistance

Nonspecific esophageal motility disorder (NEMD) represents a difficult therapeutic challenge because of the heterogeneous nature of the esophageal motor functions. We studied the effects of cisapride on the esophageal symptoms and esophageal motor function in a group of patients with NEMD showing delayed esophageal transit.Seventy eligible patients were entered into a 4-week, double-blind randomized comparison of 10 mg of cisapride or placebo, four times daily. Symptom assessment, esophageal manometry after wet swallows, and esophageal scintigraphy after intake of a liquid and solid bolus were performed in each patient before and after treatment.After 4 weeks of treatment cisapride significantly increased the prevalence of esophageal peristaltic contractions (percentage of total contractions, P0.05 versus base line and placebo) and significantly improved esophageal emptying of the solid bolus (P0.05 versus placebo) but not of the liquid bolus. Placebo did not have any significant effects versus base line on these variables. Both placebo and cisapride improved the distal esophageal amplitude versus base line (no significant intergroup differences). Symptom scores were significantly reduced after 4 weeks of treatment versus base line in both groups (no significant intergroup differences except for heartburn and regurgitation, P0.05). On global evaluation of treatment, significantly more patients in the cisapride group were rated as markedly or moderately improved, when compared with placebo.The results of the present study showed that cisapride is effective and well tolerated in patients with NEMD accompanied by delayed esophageal transit. Symptomatic improvement may possibly be related to its beneficial action on the esophageal body by increasing the number of peristaltic contractions and esophageal emptying of solids.

A systematic investigation of the structural and recording characteristics of CoPtCrO composite media with various Co alloys as well as continuous TbFeCo capping layers has been performed. For the media with a Co-alloy capping layer (M/sub s//spl sim/900 emu/cm/sup 3/), the transition jitter remains unaffected and dc noise is greatly reduced. However, for the media with low M/sub s/ capping layer or continuously exchange coupled TbFeCo capping layer, transition jitter is increased. Magnetically continuous but structurally discontinuous Co-alloy capping layers grown onto well-isolated Co grains can reduce dc noise, while maintaining low transition noise.

An anisotropy enhanced dual magnetic layer structure is proposed to improve the recording performance of perpendicular media. The initial layer is made of low noise Co-Cr-Pt-O layer and the top layer is made of higher anisotropy Co-Cr-Pt-B layer. A higher nucleation field than the single layer structures is obtained for the dual magnetic layer media. By optimizing the layer structure and properties, better signal-to-noise and lower adjacent track erasure can be achieved for the dual magnetic layer design over single magnetic layer media.

The permeability of the magnetic soft underlayer (SUL) was systematically varied through SUL structure change, and its effect on wide area adjacent track erasure (ATE) and media overwrite (OW) was studied. Results suggest that ATE decreases with SUL permeability, and it involves only a finite thickness of the SUL. OW increases with SUL permeability as well as SUL thickness. In addition, ATE is less affected by magnetic spacing than OW. Antiparallel coupled SUL (APS) improves ATE. A double-APS structure with a permeability gradient is proposed to optimize OW and ATE performance.

We discuss a method of ac-demagnetizing an entire disk using permanent magnets and compare the demagnetized states of perpendicular media with different levels of intergranular exchange. The method consists of applying a large field perpendicular to the media recording layer anisotropy direction. This bulk ac-erasure technique provides a background noise that is lower than that which can be achieved by ac-erasing with a write head. Highly exchange-coupled media exhibit low dc noise but increased ac-erased background noise. Magnetic force microscopy data show increased magnetic roughness in the ac-erased state with exchange-coupling strength. For the media with least coupling the dc noise is similar to the ac noise.

Compositionally graded magnetic multilayer (CGM) structures were investigated to improve media signal-to-noise ratio (SNR) as well as thermal stability. The medium structure consists of multiple magnetic layers that play an important role in determining the crystallographic texture as well as magnetic activation volume. Low medium noise is achieved while retaining high resolution, as the number of layers is increased. The CGM media offer a magnetic anisotropy gradient from the top to bottom layers, which enhances head writability at high frequencies without affecting thermal stability. Improved magnetic and recording properties such as high K/sub u/ V/kT, SNR, and overwrite are obtained with CGM media, suitable for high areal density recording.

A promising soft magnetic under layer (SUL) structure consisting of anti-parallel coupled soft layers (APS) is investigated to improve the performance of high-density perpendicular recording media. CoCrPt-O recording media with average grain diameter /spl sim/6 nm, coercivity of 5 kOe and nucleation field of -2 kOe is fabricated on both conventional SUL and APS. Wide-area adjacent track erasure (ATE) is observed for conventional SUL, which increases at lower interlayer spacing (t/sub IL/). APS structure enables the suppression of ATE even up to t/sub IL/=10 nm. Moreover, APS leads to reduced dc erase noise and improved signal to noise ratio particularly for SUL thicknesses

The effect of oxygen incorporation on the crystallographic, magnetic, and recording performance of perpendicular magnetic recording (PMR) oxide media was investigated. The media were prepared by dc-magnetron sputtering of CoCrPt-SiO/sub 2/ targets in an Ar/O/sub 2/ gas mixture. X-ray photoelectron spectroscopy (XPS) detected Cr-O peaks in the sputtered film, whereas no strong evidence of SiO/sub 2/ is seen. Moderate oxygen incorporation in the film (/spl sim/15 at%) promotes Cr-O formation in the grain boundary and results in a dramatic increase of coercivity H/sub c/ and signal-to-noise ratio (SNR). However, as the O/sub 2/ content is further increased, oxide incorporates into the core of the grains, resulting in decreased H/sub c/, magnetization and SNR.

Antiferromagnetically coupled (AFC) media and conventional media (CM) were compared side to side over a wide range of orientation ratios (OR). For both AFC and CM, oriented media outperform isotropic media. AFC and CM show similar signal-to-noise ratios (SNR) throughout the entire range of OR. CM exhibit good SNR performance even at M/sub r/t

The correlation between grain morphologies and magnetic properties of CoCrPt/Cr thin films was investigated by varying the sputtering deposition parameters of CoCrPt thin films. Independent of sputtering conditions, the Cr underlayer enhanced Co-grain isolation and limited grain growth in CoCrPt films, resulting in increased coercivity. Cross-sectional transmission electron microscopy indicated a strong separation of the Co grains with increasing argon sputtering pressure, due to the enhanced scattering of argon ions by sputtering particles, and thus the observed higher content of Pt in the deposited films. The Co grains separated by 10–20 A thick non-magnetic boundaries were found to grow on a single larger Cr grain, resulting in reduced exchange coupling and increased coercivity. The application of substrate bias increased the (1010) texture of the Co grains and decreased the grain size of the CoCrPt thin films. In addition, the quality of Co epitaxial growth on the Cr underlayer was enhanced by increasing bias, and the boundary layer between the Cr and CoCrPt films became less distinct as a result of interdiffusion. The magnetic field required to saturate the film increased significantly with increasing substrate bias, possibly due to the induced residual stress in the bias-sputtered films.

Transition and DC noise characteristics of longitudinal recording media were studied as a function of orientation ratio (OR). With increasing OR, a substantial decrease of DC noise is observed against the gradually increasing transition noise, resulting in the reduced media total noise. The increase in the media transition noise with OR is attributed to the increase in the cross-track correlation length s. The experimentally estimated s for the media with OR=1.8 is significantly larger than that of the media with OR=1.25, possibly resulting from the difference in magnetostatically coupled Co grains aligned to the track direction. For high-density low M/sub r/t designs, reducing DC noise by increasing OR, in spite of an increase in transition noise, becomes an effective means to increasing areal density.

The structural, magnetic, and recording properties of longitudinal recording media with CrMoB underlayer were studied and compared to those with CrMo underlayer. Media with CrMoB underlayer have smaller grain size, better grain segregation, lower coercivity, and better recording performance than media with CrMo underlayer.

A superparamagnetic CoCrRu alloy is proposed for the intermediate layer (IL) between Ru/M2 in a typical antiferromagnetically coupled media structure M1/Ru/M2 (M2: recording layer). With the presence of the IL, the exchange coupling energy (Jex) initially increases from ∼0.09 to ∼0.10 erg/cm2 and asymptotes to ∼0.056 erg/cm2 when the IL thickness reaches 11 A. Due to its superparamagnetic nature, the CoCrRu IL does not introduce extra medium noise, in contrast to the ferromagnetic CoCrPtTa IL. The vibrating sample magnetometer thermal stability ratio (KV/kT) increases from 52 to 58 with a ∼7 A CoCrRu IL, in agreement with the improved spin stand signal decay. X-ray diffraction scans indicate an improved epitaxial growth in the M2 layer when a CoCrRu IL is present.

The recording performance of perpendicular media with amorphous CoZrNb, nanocrystalline NiFeNb, and exchange-pinned FeMn/NiFeNb soft magnetic underlayers (SULs) has been studied. A method has been proposed to quantify the spike noises from the SUL. We found that media with higher permeability NiFeNb SULs showed 4 db higher signal-to-noise ratio than media with lower permeability CoZrNb SULs. The exchange-pinned NiFeNb SUL suppresses spike noise and offers good recording performance. Furthermore, the recording frequency dependence of dynamic coercivity (Hc) was strongly affected by the use of different SULs. The increase in dynamic Hc with linear density is negligibly small for media with NiFeNb SULs, whereas dynamic Hc sharply increases with increasing density for media with CoZrNb SULs.

We have successfully demonstrated longitudinal recording at areal density of 130 Gb/in2 at a data rate as high as 170 Mbps (21 MB/s) and at a bit-aspect-ratio (BAR) of 2.9, using merged inductive-write/spin-valve-read heads on low noise thin film disks. The heads were fabricated with the standard photolithography and wafer pole trimming used in our currently available commercial products. The reader is a bottom synthetic spin valve (BSSV) with a 0.09 μm gap, and the writer has a conventionally trimmed pole with 0.09 μm gap. The reader magnetic read width (MRW) was measured at 0.10 μm. At read bias of ∼4 mA we measured reader sensitivity as high as 20 mV/μm. The write head was also optimized for tracks as narrow as 0.14 μm operating at overwrite (OW) of 36 dB and nonlinear transition shift (NLTS) better than −25 dB at 610 kBPI, without precomp. Using conventional media we measured total spectral SNR∼18 dB. The media to electronics noise ratio was 4.8, showing that we are still operating in a media noise li...

We have studied thermal stability and recording characteristics of CoCrPtB alloy media with varying c axis anisotropy dispersion, preferred orientation (PO), and in-plane orientation ratio (OR) on both glass and NiP-plated Al substrates. With increasing in-plane c axis orientation and OR, improved recording performances such as lower pulsewidth, lower media transition noise, and lower dc noise are achieved. Thermal decay rate is primarily determined by Co anisotropy dispersion and in-plane OR for the same coercivity media. Media having a large out-of-plane c axis component exhibit a wide switching field distribution and have a high signal decay rate. The PW/sub 50/ and dc noise of media with out-of-plane Co grains are very sensitive to changes in write field. On the other hand, highly oriented media having high OR are less sensitive to head writability variations and offer good thermal stability with excellent recording performance.

Summary form only given. Perpendicular magnetic recording (PMR) media has been considered as a promising candidate in order to achieve over 100 Gbir/in2 recording density. However, thermal stability at low recording densities has been a concern especially for low-noise PMR media. Achieving high perpendicular HC and unity squareness (SQ=Mr/Ms) is necessary to improve thermal stability and has been proposed by using either high substrate temperature or post annealing in CoCr based alloy. However, the influence of high heating on recording performance deserves further investigation. In this work, we studied on the seedlayer and heating effects on the crystallographic, magnetic and recording properties of CoCr18Pt16B4 granular PMR media. The CoCrPtB films were sputtered on preheated glass substrates with a Ru underlayer (UL) or a Ta/Ru UL on top of a 300-nm-thick NiFe17Mo4 soft magnetic underlayer. We report that Ta/Ru UL developed in this study greatly enhances Ru(0002)/Co(0002) crystallography, HC, SQ and thermal stability without degrading media signal-to-noise ratio (So/Nm).

Magnetoresistance (MR) and Planar Hall effect (PHE) of Ta 50 A/NiFe 60 A/Co 90 Fe 10 10 A/Cu 20 A/Co 90 Fe 10 10 A/NiFe 23 /AFeMn 100 A/Ta 50 A spin valve were measured with the magnetic field applied in the plane of the sample. A single batch thin film was etched parallel and perpendicular to the easy direction of the pinned layer. When the field and current were applied along the easy direction, we observed a clear evidence of before- and after-domain rotation of the free layer, near H =0. Larger after-domain rotation of the free layer effect was observed in the sample etched along the hard axis, because the shape anisotropy tilted bias field made the hysteresis of the pinned layer have a longer tail beyond H >0.

The effect of surface roughness on magnetoresistance (MR) and magnetic properties of Ta/NiFe films is investigated as a function of surface roughness and NiFe thickness. The surface roughness effects on the MR ratio, Δρ/ρ, of Ta/NiFe films can be separated into two different regimes. In regime I, Δρ/ρ of NiFe films linearly decreases with increasing roughness mostly due to the increase in resistivity of NiFe, while Δρ remains constant. In regime II at increased roughness, domain wall pinning is induced by surface roughness causing a degradation of the uniaxial anisotropy of NiFe and leading to the decrease in Δρ, resulting in the steeper MR ratio decrease. The change in MR properties of NiFe films with varying thicknesses can be correlated with the change in surface resistivity, ρs. Strongly textured NiFe(111) grown onto smooth substrate yields higher anisotropy and lower coercivity than those deposited onto rough substrates over a wide range of NiFe thicknesses.

The effect of magnetostriction (MS) on the device characteristics of soft-adjacent-layer (SAL) biased magnetoresistive (MR) head was investigated. As MS changes from -7/spl times/10/sup -7/ to 1.77/spl times/10/sup -6/, the magnetic track width increases from 1.26 to 1.83 /spl mu/m. Asymmetry of bias point, output sensitivity, and output amplitude are also affected by the stress induced anisotropy. The variation of magnetostriction (/spl Delta//spl lambda/=2/spl times/10/sup -6/) induces the change in bias field by 60 Oe associated with the estimated stress of +800 MPa on the MR stripe.

We report a simple, nondestructive B-H looper bending method for measuring 10/sup -7/ of magnetostriction (/spl lambda/) in thin films (/spl sim/150 /spl Aring/). The new method improves the accuracy and repeatability of /spl Delta/H/sub k/ measurements in loopers by employing a measurement sequence that corrects the non-repeatable balance errors. For the 150 /spl Aring/ thick NiFe films under an anisotropic strain of 4.6/spl times/10/sup -5/, we achieved a /spl Delta/H/sub k/ repeatability, 1/spl sigma/=0.009 Oe which is equivalent to 3.4/spl times/10/sup -8/ in /spl lambda/. Our technique gives /spl lambda/ values that agree well with the optical cantilever bending technique and can be easily utilized in a thin-film head production environment for accurate control of /spl lambda/.

The interface magnetostriction (MS), /spl lambda//sub i/ of NiFe films (thicknesses:50 to 500 /spl Aring/) encapsulated with Ta and Al/sub 2/O/sub 3/ layers was studied in as-deposited and thermally annealed states. The MS of NiFe films encapsulated with only Ta (or Al/sub 2/O/sub 3/) layers increase (or decrease) rapidly with decreasing NiFe thickness, due to giant positive (or negative) /spl lambda//sub i/. The magnitudes of both positive and negative /spl lambda//sub i/ increase noticeably with processing at elevated temperatures. In structures containing Ta/NiFe and NiFe/Al/sub 2/O/sub 3/ interfaces, the total interfacial MS contribution is greatly reduced due to the opposite signs of /spl lambda//sub i/ at NiFe interfaces, leading to negligible thickness dependence of the effective MS in as-deposited and annealed states. The strong interfacial MS induced anisotropy affects markedly the uniaxial anisotropy of NiFe films for thicknesses below 100 /spl Aring/.

FeMn based spin valves exhibiting high GMR ratio and high exchange bias field were fabricated by improving the interface roughness as well as the crystallographic texture. A highly oriented (111) NiFe free layer deposited with substrate bias promoted strong (111) textures of Cu and FeMn while maintaining sharp interfaces, resulting in a high exchange bias field, a high blocking temperature, and a high GMR ratio. The correlation between the interlayer coupling energy (J/sub free-pinned/) and the interface sharpness was studied as a function of Cu spacer thickness for spin valves with free and pinned NiFe layers deposited under various bias conditions.

Perpendicular magnetic recording (PMR) has been recognized for many years as having the potential to extend recording densities beyond the capabilities of longitudinal recording. This paper discusses the challenges in designing perpendicular thin-film recording media materials.

A spin-stand level dynamic read-back microscopy (DRM) technique offers ease of use and full compatibility with standard media parametrics testing. We designed and implemented a DRM tester based on a LeCroy DDA5005 oscilloscope and a Guzik spin-stand. Using a DRM, we investigated the effect of magnetic exchange coupling on side erasure of CoCrPt-SiO PMR media. Exchange was controlled by varying the oxygen partial pressure during deposition. The paper show tracks after a progressive edge-trimming from the both sides using a low DC-negative erase current.

This paper compares the images obtained by superparamagnetic and permanent magnetic force microscopy (MFM) tips, that allows us to explain the issues related to the frequency double in some of domain images of the recording media. This paper also investigates the domain structures of high density recording bits (up to 1100 kfci) written on ac and dc-erased CoPtCrO perpendicular magnetic recording (PMR) media with permanent magnet MFM tips under ambient conditions.

A systematic investigation of the magnetic and recording characteristics of reactively sputtered CoPtCr-(Si-O, Ti-O, Cr-O) media has been performed. The optimum oxidation condition for media with well-isolated Co grains, high coercivity (Hc) and nucleation field (Hn), and superior media noise performance strongly depends on the oxide type. Despite differences in the optimum oxidation condition, the highest achievable Hc and Hn are similar. The transition jitter and magnetic write width are mainly determined by the magnetic exchange coupling depending on the oxidation condition but not by the oxide type

In this study, the effect of process parameters on magnetic and recording properties of MiniDiscs is reported. Processes have been tailored to optimize the recording performance of MiniDiscs, such as carrier-to-noise ratio (CNR) at low magnetic fields, recording power margin, and recording power threshold. At higher deposition pressures or lower deposition rates of TbFeCoCr, the external bias field sensitivity of the carrier becomes worse but the noise at high bias fields (>200 Oe) decreases, resulting in improved CNR at high bias fields. Disks with TbFeCoCr sputtered at low pressure or high deposition rates produce a high error rate at high recording power (>4.5 mW), due to jitter noise caused by interference of neighboring magnetic domains. The power margin of the disks is strongly affected by the pressure and deposition rate of TbFeCoCr. When the Curie temperature of the TbFeCoCr layer is lowered by 30 °C (alloy change), the power margin decreases significantly and CNR is decreased by ∼2 dB because of ...

We report, for the first time, coercivity values greater than 2000 Oe with Mrt values of 3.0 memu/cm2 for Cr/CoPt12Cr13 and Cr/CoPt20 bilayer films deposited by dc magnetron sputtering at room temperature. CoPtCr films sputtered at a deposition rate of 98 A/s and high bias voltage showed Hc of 1965 Oe with Mrt of 3 memu/cm2, while CoPt films sputtered at 99 A/s and moderate substrate bias showed Hc of 2350 Oe with Mrt of 3 memu/cm2. X-ray diffraction studies indicated that Co(10.0) and (11.0) texture leading to in-plane orientation of c axis are promoted in the films sputtered at high deposition rate and bias conditions. Furthermore, the grain-to-grain epitaxy between the Cr underlayer and the Co alloy layer as well as the dense Co grains growing in a columnar shape without voids resulted in higher Hc and Mrt without degradation of coercive squareness. Plots of vs Mrt for films deposited under the optimum bias conditions offer a wide range of useful Hc and Mrt combinations for hard bias applications in ma...

Strongly textured NiFe(111) underlayers, deposited by dc magnetron sputtering with applied substrate bias, are utilized to grow large, epitaxial grains of FeMn(111). These perfectly oriented (111) NiFe/FeMn bilayers exhibit the highest interfacial exchange anisotropy energy (0.17 erg/cm2), lowest coercivity (∼2 Oe) of the pinned layer, and highest blocking temperature (205 °C) ever reported, to the best of our knowledge. The relationship between the blocking temperature and the x-ray diffraction intensity of FeMn(111) indicates that the exchange interaction across the NiFe and FeMn interface is enhanced by the well-oriented, large, defect-free FeMn(111) crystals.

The effect of NiFe texture on the exchange coupling field and coercivity of Ta/NiFe/FeMn films was studied by varying the deposition conditions of dc magnetron-sputtered NiFe films. By decreasing argon pressure or by increasing substrate bias, strongly textured, large grains of NiFe(111) were grown, yielding highly oriented FeMn(111) texture. Well oriented NiFe(111)/FeMn(111) films yielded the highest exchange anisotropy (0.14 erg/cm/sup 2/), lowest coercivity (/spl ap/2 Oe), and highest blocking temperature (200/spl deg/C) ever reported.

The effect of the soft underlayer (SUL) permeability on adjacent track erasure (ATE) as well as on the recording performances of the media was investigated and verified. The 3 structures used were: single layer CoZrTa, and the antiferromagnetically coupled SULs (APS) CoZrTa/Ru/CoZrTa and CoZrTa/Ru/Co/CoZrTa. All samples were deposited on NiP-plated AlMg disk substrates. The 240 tracks were written once with 45 mA at 60 kfci and the stressing track was written for 32,000 revolutions with 55 mA at 360 kfci. Similar to previous observations, the APS structure largely suppressed the ATE. It was found that the total amount of flux an SUL is capable of conducting does not correlate well with ATE. However, ATE correlates well with permeability, suggesting that material property alone determines ATE.