The firstprinciple calculation within densityfunctional theory is used to investigate the hypothetical zincblende structured vbi. Direct evidence for a halfmetallic ferromagnet article pdf available in nature 3926678. A halfmetal is any substance that acts as a conductor to electrons of one spin orientation, but as an insulator or semiconductor to those of the opposite orientation. Exchange coupling of a perpendicular ferromagnet to a half. It aims to exploit the spin degree of freedom in order to realise advanced electronic devices. The zb tite is a complete halfmetal with minority spin gap about 2. Pdf halfmetallic ferromagnets and spin gapless semiconductors. Although the powder diffraction pattern can be fitted by the reported crystal structure including a single cr site, the atomic pair distribution function pdf can be fitted by the structural model with an orthorhombic unit cell including. The band structure calculation shows that co2cral is a true halfmetallic ferromagnet with a magnetic moment. Sep 18, 2010 we present the study of half metallacity of co2mnal as half heusler alloy in l21 structure which consists of four interpenetrating fcc sublattices. We demonstrate that combining standingwave sw excitation with resonant inelastic xray scattering rixs can lead to depth resolution and interface sensitivity for studying orbital and magnetic excitations in correlated oxide heterostructures. A rutile structure halfmetallic ferromagnet 368 vi.
Many of the known examples of halfmetals are oxides, sulfides, or heusler alloys in halfmetals, the valence band. The sign in each parenthesis represents the sign of the amr ratio observed experimentally. Magnetic properties at surface boundary of a halfmetallic. Depthresolved resonant inelastic xray scattering at a. Apart from a polarization value as close as possible to unity, halfmetals must have also other properties in order to be functional. Hmfs have unique properties, in which the majority spins have a metallic band structure, whereas the minority spins have a semiconducting band with the fermi level e f lying within an. Our results highlight a new promising graphenelike half metallic ferromagnetic material for. In this study, we first derive a general expression of the amr ratio extending the conventional model 1 to a more general one 2 4. These devices do not need any external magnetic field but make use of their own magnetization. The ferromagnet we use, cro 2, is a socalled halfmetallic ferromagnet 6. Although all halfmetals are ferromagnetic or ferrimagnetic, most ferromagnets are not halfmetals. This work reports on a spectroscopic investigation of thin co 2 mnsi films as they are used as electrodes in magnetic tunnel junctions.
University of groningen halfmetallic ferromagnets katsnelson. Charge dynamics in the halfmetallic ferromagnet cro 2. Exchange interactions and critical temperatures in halfmetallic compounds 370 a. Halfmetallic ferromagnetism in the hypothetical zinc. Further we also found that a moderate change of the lattice parameters does not change the halfmetallic ferromagnet hmf behavior for both materials. We suggest memory and spin injection devices fabricated with halfmetallic materials and based on the anomalous hall effect. Spintronics is a new and emerging field in nanotechnology, which has been evolving rapidly. In a magnetic weyl semimetal with broken timereversal symmetry, there are significant contributions on. Spin injection devices made in thin film form are also suggested. An antiferromagnetic halfmetallic semiconductor of the present invention is manufactured by adding to a semiconductor two or more types of magnetic elements including a magnetic element with a delectron number of less than five and a magnetic element with a delectron number of more than five, and substituting a part of elements of the semiconductor with the two or more. Density functional theory based electronic structure calculations will be performed by using the fullpotential linear augmented plane wave fplapw. A new class of halfmetallic ferromagnets is found in the rutile structure. Xray diffraction and rutherford back scattering experiments indicated that the deposited nimnsb exhibited the desired structure and composition.
When the magnetization configuration of the hmf source and drain is parallel antiparallel, highly spinpolarized. Using the korringakohnrostoker method kkr combined with the coherent potential approximation in the framework of firstprinciple calculations, we study the half metallic ferromagnetic. The halfmetallic ferromagnet has 100% spin polarization for the conduction electrons, and thus it offers. Swrixs has been applied to multilayer heterostructures consisting of a superconductor la1. Mar 23, 2004 we propose and theoretically analyze a metaloxidesemiconductor fieldeffecttransistor mosfet type of spin transistor spin mosfet consisting of a mos structure and halfmetallicferromagnet hmf contacts for the source and drain. The critical components beta, gamma, and delta determined using the. It exhibits a secondorder paramagneticferromagnetic phase transition with tc 174 k.
Ferromagnetinsulatorferromagnet tunneling with one half. The ferromagnetism, arising from the itinerant cr d electrons, introduces intrinsic halfmetallicity in cr 2 c mxene, with the halfmetallic gap as large as 2. Journal of magnetism and magnetic materials 2017, 433, 222226. The origin of anomalous hall effect ahe in magnetic materials is one of the most intriguing aspect in condensed matter physics and has been controversial for a long time. It has an integer magnetic moment of 1 b per unit cell and a spinpolarized band structure with a. Due to the ferromagnetic decoupling, one of the spin subbands generally the majorityspin or upspin subband is metallic, whereas the fermi level falls into a gap of the other. Half metals are materials characterized by spin dependent band structures that exhibit properties of both insulators and metals.
In a half metallic ferromagnet, electrons of one spin have a band gap at the fermi energy akin to an insulator or semiconductor and those with the opposite spin have a high population of states at the fermi energy. We also demonstrate a ferromagneticantiferromagnetic transition accompanied by a metal to insulator transition in cr 2 c, caused by surface functionalization with f, oh, h, or. Study of co2mnal heusler alloy as half metallic ferromagnet. Anisotropic magnetoresistance effects in fe, co, ni, fe4n. It has a perovskite based crystal structure, which has the general form abo 3. Spinpolarized tunneling in a halfmetallic ferromagnet. Although all half metals are ferromagnetic or ferrimagnetic, most ferromagnets are not half metals. The half metallic heusler compound co 2 mnsi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. Chromium dioxide is a bad metal at room temperature but it has a remarkably low residual resistivity cm despite the small spectral weight associated with free carrier absorption.
We have performed powder neutron diffraction on the halfmetallic ferromagnet cro 2 which has a rutiletype crystal structure with a tetragonal unit cell. B unit, and this half metallic behavior can be maintained for larger strains. For the minorityspin direction the fermi level lies in a 1. That is, the electrons responsible for the metallic behavior share the same spin. Large intrinsic anomalous hall effect in halfmetallic. The electronic transport is metallic for the spinup electrons, while it is. Read the effect of lanthanide impurities on the physical properties of halfmetallic ferromagnet co 2 mnsi, applied surface science on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. Effect of 0001 strain on the electronic and magnetic. Half metallic ferromagnets and spin gapless semiconductors. We have investigated the critical behavior of a shanditetype halfmetal ferromagnet co3sn2s2. Study of co2mnal heusler alloy as half metallic ferromagnet article pdf available in indian journal of physics 846. Halfmetallic ferromagnets and spin gapless semiconductors. In a halfmetallic ferromagnet, electrons of one spin have a band gap at the fermi energy akin to an insulator or semiconductor and those with the opposite spin have a high population of states at the fermi energy.
Hi n wm s hi must be immense in a ferromagnet like iron to be able to induce a signi. In addition, we observe different depth distribution of the rixs excitations. Schematic diagrams of the memory chips, in thin film and bulk crystal form, are presented. The magnetization m versus applied magnetic field h isotherm. Its halfmetallicity could be maintained within a relatively wide range of. The investigated films exhibit a remanent inplane magnetization with a. We will use the general gradient approximation method gga and. Cro2 predicted as a halfmetallic ferromagnet iopscience. Lichtenstein1 1university of nijmegen, nl6525 ed nijmegen, the netherlands 2institute of metal physics, 620219 ekaterinburg, russia 3department of physics, uppsala university, box 530, se75121 uppsala, sweden received 24 march 2003.
Memory and spin injection devices involving half metals. New bandgap measurement technique for a halfmetallic. Halfmetallic ferromagnetism in the hypothetical zincblende. A half metal is any substance that acts as a conductor to electrons of one spin orientation, but as an insulator or semiconductor to those of the opposite orientation. Our results highlight a new promising graphenelike halfmetallic ferromagnetic material for. Local structural analysis of halfmetallic ferromagnet. Nonquasiparticle states in the halfmetallic ferromagnet nimnsb l. We have investigated the critical behavior of a shanditetype half metal ferromagnet co3sn2s2.
We present the study of half metallacity of co2mnal as halfheusler alloy in l21 structure which consists of four interpenetrating fcc sublattices. B unit, and this halfmetallic behavior can be maintained for larger strains. Robust halfmetallic ferromagnetism in cr 3 c 2 mxene. With the recent improvement in the storage media devices following to the discovery of giant magnetoresistance effect, it is envisioned that the electronic devices have several advantages. In addition, we show that the negative amr ratio is a necessary condition for halfmetallic ferromagnets 2,3,5,6,7. A practical approach for stabiliz ing the crsb compound in the metastable zb structure is the pseudo morphic growth of crsb thin film on zb semiconductors. In a magnetic weyl semimetal with broken timereversal symmetry, there are significant. In the crystal, the a sites are occupied by lanthanum and strontium atoms, and the b sites are occupied by the smaller manganese atoms. Exchange coupling of a perpendicular ferromagnet to a halfmetallic compensated ferrimagnet via a thin hafnium interlayer. Appearance of halfmetallicity is consistent with the integral magnetic moments, which. Thus, the electronic properties of this organometallic wire. The band structure calculation shows that co2cral is a true halfmetallic ferromagnet with a. Recent studies indicate that the intrinsic ahe is closely related to the berry curvature of occupied electronic states. Direct measurement of the conduction electron spin polarization p in epitaxial nimnsb was performed to test the prediction of half metallicity in this material.
Halfmetallic ferromagnetism and surface functionalization. Using the general expression, we next give the intuitive explanation about the amr effect 3. The half metallic ferromagnet has 100% spin polarization for the conduction electrons, and thus it offers. Charge dynamics in the halfmetallic ferromagnet cro 2 by. The band structure calculation shows that co2cral is a true half metallic ferromagnet with a magnetic moment. Intuitive explanation of anisotropic magnetoresistance. Easily observable sw effects on the rixs excitations were found in these lscolsmo multilayers. State of co and mn in halfmetallic ferromagnet co2mnsi. Fermiology and transport properties of the halfmetallic. Halfmetals are materials characterized by spin dependent band structures that exhibit properties of both insulators and metals. Intuitive explanation of anisotropic magnetoresistance amr.
University of groningen nonquasiparticle states in the. University of groningen nonquasiparticle states in the half. Half metallic ferromagnetism fm in singlecrystal ba0. In addition, we show that the negative amr ratio is a necessary condition for half metallic ferromagnets 2,3,5,6,7.
Aonedimensional halfmetallic ferromagnet volodymyr v. M sb shows the full moment at very low temperature but decays much faster than the bulk magnetization \m b \ upon heating. Ferromagnet insulator ferromagnet fmifm tunnel junctions were prepared with one ferromagnet being nimnsb, a compound predicted by degroot et al. Our calculations indicate that the zbtype vbi is predicted to be a true halfmetallic ferromagnet with a magnetic moment of 2. Halfmetallic ferromagnetism in the zincblende tite. We propose and theoretically analyze a metaloxidesemiconductor fieldeffecttransistor mosfet type of spin transistor spin mosfet consisting of a mos structure and halfmetallicferromagnet hmf contacts for the source and drain. The ferromagnet we use, cro 2, is a socalled half metallic ferromagnet 6. Ferromagnetinsulatorferromagnet fmifm tunnel junctions were prepared with one ferromagnet being nimnsb, a compound predicted by degroot et al. The halfmetallic heusler compound co 2 mnsi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. Spinpolarized tunneling in nimnsbal 2 o 3 al junctions showed p of 28%, contrary to the predicted value of 100%. Charge dynamics in the halfmetallic ferromagnet cro2. In the crystal, the a sites are occupied by lanthanum and strontium atoms, and the b sites are occupied by. We will use the general gradient approximation method gga and local density approximation.
The electronic transport is metallic for the spinup electrons, while it is insulating for the spindown electrons, a. The critical components beta, gamma, and delta determined using the modified arrott plot, the. Local structural analysis of halfmetallic ferromagnet cro2. Direct evidence for a halfmetallic ferromagnet nature. Using firstprinciples calculations within generalized gradient approximation, the electronic and magnetic properties of zinc blende zb crpmnp superlattice. Spinresolved photoelectron spectroscopy of oxidic half. The zb tite may be epitaxially grown on cdte substrate. Study of co 2 mnal heusler alloy as half metallic ferromagnet. The halfmetallic nature of zb tite exists within a wide range of lattice constant. This means that kcrse2 is a halfmetallic ferromagnet. A spin triplet supercurrent through the halfmetallic. Highlights the nm nias is the ground state of tite and fm zb phase becomes stable at.
Electronic structure of the halfmetallic ferromagnet kcrse2. Pdf halfmetallic ferromagnetism in tmdoped mgh 2 hydride. Straininduced halfmetallic ferromagnetism in zinc blende. New bandgap measurement technique for a half metallic ferromagnet alhuwaymel, tariq fahad h 2015 new bandgap measurement technique for a half metallic ferromagnet. We suggest memory and spin injection devices fabricated with half metallic materials and based on the anomalous hall effect. Critical behaviors of halfmetallic ferromagnet co3sn2s2. Infrared spectroscopy is used to investigate the electronic structure and charge carrier relaxation in crystalline films of cro2 which is the simplest of all halfmetallic ferromagnets.
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