Giant Magnetization Research Articles

Self-interaction correction for band structure calculation based on local density approximation of iron nitrides

The band theory based on the conventional local density approximation (LDA) has not given a quantitative explanation of the mechanism of the giant magnetization of α″-Fe 16N 2 thin film. In this paper, the self-interaction correction (SIC) is applied to the LDA band calculation of α″-Fe 16N 2. The electronic structure is calculated by the self-consistent linearized augmented plane wave (LAPW) method. It can be concluded that the influence of the SIC for α″-Fe 16N 2 is large, although the calculated electronic structures of 3d transition metals and γ′-Fe 4N are little affected by the SIC. The charge density distribution of α″-Fe 16N 2 is uniformly broadened. It appears that the distribution for some sites of Fe atoms in α″-Fe 16N 2 is different from that of bcc Fe atoms. However, the SIC has little effect on the total magnetic moment. The SIC is unable to explain the giant magnetic moment. It seems that the orbits of iron nitride are probably metallic bond-like, whose orbit is Bloch function-like, although the localization of some sites of Fe atoms of α″-Fe 16N 2 results in more influence than that of γ′-Fe 4N.

Correlation between giant magnetoresistance and magnetization in metallic superlattices: a comparison of perpendicular and in-plane geometries

The problem of perpendicular and in-plane spin-dependent transport in magnetic superlattices is treated within a unified semi-classical approach. By starting from the Boltzmann equation with exact boundary conditions, we calculate the magnetoresistance in both geometries. A correlation between the giant magnetoresistance and the superlattice magnetization is also considered.

Magneto-optical indicator film observation of domain structure in magnetic multilayers

A new method is developed using a transparent indicator ferrimagnetic magneto-optic film with in-plane anisotropy for visualization and direct experimental study of dynamic magnetization processes and nondestructive characterization of the defect structure of magnetic multilayers. Some examples of its application to the investigation of peculiarities of the as-grown magnetic structure of electrochemically produced CoNiCu/Cu multilayers with a giant magnetoresistance (GMR) effect and magnetization reversal by domain wall motion are described.

Mechanical alloying of immiscible Cu70TM30 alloys (TM = Fe,Co)

Abstract Four series of copper-based alloys with compositions Cu70Co30, Cu70Fe30Cu70Co15Fe15 and Cu70(CoFe)30 were synthesized by mechanical alloying (MA). The interest in these materials is as parents of alloys which will show the giant magnet resistance (GMR) effect. The structural evolution was studied as a function of the MA time by means of Mossbauer spectroscopy, X-ray and neutron diffraction techniques and differential scanning calorimetry (DSC). In spite of the positive heat of mixing of the alloy constituents, the complete dissolution of the minority phases (iron and/or cobalt) into the copper f.c.c. lattice was observed for each specimen after 16 h of MA. This alloying was accompanied by changes in lattice parameter ─Δa 0/a 0─ of up to 0.5% with respect to pure copper. Analysis of the crystallization products arising from DSC treatments up to 600°C revealed a separation into copper f.c.c. and iron-based b.c.c. phases. In the case of the ternary Cu70(FeCo)30 alloys, the FeCo intermetallic compoun...

Calculated magnetic properties of Gd/W superlattices

The recently observed giant magnetization in Gd/W superlattices has been investigated theoretically using local density functional theory and the linear-muffin-tin-orbitals method. Two idealized structural models were considered but for neither do we find magnetic moment enhancements over the bulk values.

Mössbauer study on Fe16N2 films prepared by ion-implant nitrification of iron films

Mössbauer spectroscopy was carried out to elucidate the magnetic structure of Fe16N2 with the giant magnetization. Samples were prepared by ion-implant nitrification of single-crystal iron films, followed by an annealing at 150 °C for 60 h. The nitrification developed three Fe atom environments, attributable to three different Fe sites in Fe16N2 structure. The magnetic moments of the first, second, and third nitrogen neighbor Fe atoms were determined to be 1.3, 2.5, and 3.8 μB, respectively. The quadrupole effect in Fe16N2 was interpreted consistently on the basis of the consideration that the magnetization is directed along [001] and nitrogen atoms had a negative charge.

Ion extraction from microwave plasma excited by ordinary and extraordinary waves and applications to the sputtering deposition

The right hand circularly polarized waves propagating along the magnetic flux are the most useful for producing overdense plasma. Microwaves channeled perpendicular to the magnetic flux are also efficient for some applications, including conductive-film preparations by sputtering and chemical vapor deposition (CVD) processes. In this study, the plasma excitation by means of the ordinary and extraordinary microwaves have been investigated for conductive film deposition. These waves effectively generate plasma with an approximately cut off density in a low-gas-pressure atmosphere. Ion streams with 4 mA/cm2 current density are extracted from the plasma excited by the extraordinary microwaves under a pressure below 0.02 Pa. These waves are used for the sputtering deposition of conductive films, including iron-nitride films with giant magnetization and Mo films.

Giant monolayer magnetization of Fe on MgO: A nearly ideal two-dimensional magnetic system.

Studies of the structural, electronic, and magnetic properties of a model 3d ferromagnetic metal-ceramic interface system Fe/MgO(001) by the full-potential linearized augmented-plane-wave total-energy method are reported. Surprisingly, the electronic and magnetic properties of a monolayer of Fe on MgO(001) substrate (magnetic moment M=3.07${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$) are remarkably close to that of a free-standing Fe monolayer (with a giant moment M=3.10${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$), as a result of the lack of electronic interaction between Fe and MgO. (The charge transfer at the Fe/MgO interface is less than 0.05 e/atom and so any direct chemical interaction between Fe and MgO is unlikely.) Thus, this system might be an ideal two-dimensional system for studying other phenomena such as magnetic anisotropy, phase transitions, and critical behavior. For two layers of Fe on MgO, i.e., 2Fe/MgO(001), the top layer Fe(M=2.96${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$) shows features close to that of a free bcc Fe(001) surface (M=2.96${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$). Significantly, the magnetic moment of the Fe layer that interfaces the MgO substrate (M=2.85${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$) is also largely enhanced from the subsurface moment (2.35${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$) in bcc Fe(001), again indicating an extremely weak effect from the MgO substrate.

Probing Giant Magnetization Clouds with Polarized Neutrons

Probing Giant Magnetization Clouds with Polarized Neutrons

Giant magnet installed at rutherford laboratory

Giant magnet installed at rutherford laboratory

OPHTHALMIC GIANT MAGNET: INQUIRIES SOUGHT

Medical Journal of AustraliaVolume 2, Issue 26 p. 1180-1180 Correspondence OPHTHALMIC GIANT MAGNET: INQUIRIES SOUGHT First published: 01 December 1967 https://doi.org/10.5694/j.1326-5377.1967.tb27381.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume2, Issue26December 1967Pages 1180-1180 RelatedInformation

Giant magnets in industry

Giant magnets in industry

Giant Magnet in Ophthalmic Casualties

Giant Magnet in Ophthalmic Casualties

The Giant Magnet in Ophthalmic Battle Casualties

The Giant Magnet in Ophthalmic Battle Casualties

LOCALIZATION OF INTRAOCULAR FOREIGN BODIES BY MEANS OF THE CONTACT LENS

The war and the war industries make the consideration of the treatment of intraocular foreign bodies opportune. Surgeons who heretofore have had little experience with intraocular foreign bodies are being called on to treat many injuries of this type. Roentgenologists likewise are feeling more poignantly their responsibility in this field. Naturally the question arises as to which methods of treatment are superior. After the use of various technics, I have found the procedures here described best adapted to the problem. The choice of surgical procedure for the extraction of foreign bodies seems to be changing. Many surgeons with much experience in the handling of intraocular injuries are giving up the use of the giant magnet entirely, and others use it only in rare instances. The grosser technic of the giant magnet has not satisfied the surgeons' desire for refinement and has failed to produce results comparable to those achieved with

A METHOD OF ELIMINATING ARCING IN THE FOOT SWITCH OF AN EYE MAGNET

In using the old type giant eye magnet for removing intraocular foreign bodies, a disconcerting electric arc and a crackling noise emanate from the foot switch, accompanied by smoke resulting from the burning of the switch contacts. This requires frequent cleaning of the contacts, and at times replacement of the affected parts may be necessitated. A more important consideration is the annoyance to the operator and the frightening effect on the patient. The physical principles involved producing these undesirable manifestations are simple, although measurement and calculation are rather complex mathematically. The coil of the magnet is supplied by a direct current, and this creates a powerful magnetic field the core. When the current is broken, the sudden collapse of this field generates, by self induction, an extremely high voltage, which instantly flows back along the lead in wires and jumps the gap which is produced as the

The technique of extraction of intraocular foreign bodies

Lose no time as infection may have time to set in or fragment may become embedded. X-ray is not needed for magnetic foreign bodies in the majority of cases. 1. (a) 70 to 80 per cent can be pulled forward from the posterior part of the eye, through the vitreous, around the lens, into the posterior chamber by a good giant magnet. 2. (b) If imbedded in the wall of the eye, this is impossible. Then localization is essential. There are three important means: (1) careful study of the path of the foreign body; (2) x-rays, which give pretty close localization but not so precise that one can be sure to cut down exactly on the foreign body; (3) for exact final localization, a short tip of a good hand magnet applied to the sclera tentatively and systematically over the suspected area. The tip is pressed lightly on the sclera and then lifted a couple of millimeters and again applied and lifted. The slight bulging of the sclera and the slight sensation of attraction reveal the exact site of the foreign body. Access to the posterior part of the eye is possible, as in operations for separated retina, by temporary section of a rectus muscle and the use of a good retractor (nonmagnetic). Cutting through the wall of the eye by the thrust of a Graefe knife may cause damaging hemorrhage. To avoid this use a diathermy knife. It is not necessary to probe the vitreous with the magnet or even to penetrate the vitreous if the foreign body has been precisely localized. Application to the lips of the wound suffices if the magnet is a good one. Avoid a giant magnet for foreign bodies that are within 2 or 3 mm. of the magnet. Avoid extensions applied to the giant magnet to act as hand magnets. After extracting diasclerally, apply a ring of diathermy micro-punctures around the site of the scleral wound to forestall separation of the retina. Results, especially late or end results, of extraction by the anterior route with the giant magnet are much better than final results with diascleral extraction by the old method, still widely used. Statistics are not available for the more modern technique here described. Details of technique for foreign bodies, magnetic and non-magnetic in different parts of the eye—cornea, anterior chamber, posterior chamber, lens, vitreous, imbedded in the wall of the eye. Importance of good light. Six causes of failure: Most important is inadequate equipment. What constitutes adequate equipment and how to test it. Hand magnet in contact should pull a fragment well over 5,000 times its weight. Giant magnet at 20 mm. should pull a fragment well over fifty times its weight. Obviously, a magnet pulling fifty will fail oftener than one pulling eighty.

The giant magnet and metallic intraocular foreign bodies

The giant magnet and metallic intraocular foreign bodies

Laceration of Retina

Laceration of detached retina is important for diagnosis and prognosis. In one case traumatic laceration was caused by a giant magnet extracting a piece of steel. In a case of spontaneous tear a vessel crossed the opening which was invisible eight months later. Studied in the University Eye Clinic of Prof. Meller, Vienna. Laceration of detached retina is important for diagnosis and prognosis. In one case traumatic laceration was caused by a giant magnet extracting a piece of steel. In a case of spontaneous tear a vessel crossed the opening which was invisible eight months later. Studied in the University Eye Clinic of Prof. Meller, Vienna.

Steel in the Vitreous. Case Report with Notes

A small fragment of steel situated almost on the retina was not drawn forward by the giant magnet in front of the cornea. Later iris scissors applied to the magnet and introduced thru a scleral incision and repeatedly snipped brought away the particle. The track thru the lens cleared and standard vision was regained.