We have performed powder neutron diffraction on the halfmetallic ferromagnet cro 2 which has a rutiletype crystal structure with a tetragonal unit cell. We present the study of half metallacity of co2mnal as halfheusler alloy in l21 structure which consists of four interpenetrating fcc sublattices. The band structure calculation shows that co2cral is a true halfmetallic ferromagnet with a. The electronic transport is metallic for the spinup electrons, while it is insulating for the spindown electrons, a. 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. To investigate the nature of the magnetic phase transition, a detailed critical exponent study has been performed. The half metallic heusler compound co 2 mnsi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. 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. 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. Hi n wm s hi must be immense in a ferromagnet like iron to be able to induce a signi. University of groningen nonquasiparticle states in the half. University of groningen nonquasiparticle states in the. Halfmetallic ferromagnetism and surface functionalization.
Although all half metals are ferromagnetic or ferrimagnetic, most ferromagnets are not half metals. In a magnetic weyl semimetal with broken timereversal symmetry, there are significant contributions on. Appearance of halfmetallicity is consistent with the integral magnetic moments, which. Fermiology and transport properties of the halfmetallic. Recent studies indicate that the intrinsic ahe is closely related to the berry curvature of occupied electronic states. Straininduced halfmetallic ferromagnetism in zinc blende. Halfmetallic ferromagnetism in the hypothetical zinc. The critical components beta, gamma, and delta determined using the modified arrott plot, the. Swrixs has been applied to multilayer heterostructures consisting of a superconductor la1. 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. 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.
When the magnetization configuration of the hmf source and drain is parallel antiparallel, highly spinpolarized. Exchange coupling of a perpendicular ferromagnet to a half. Halfmetallic ferromagnets and spin gapless semiconductors. 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. 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. Pdf halfmetallic ferromagnetism in tmdoped mgh 2 hydride. Easily observable sw effects on the rixs excitations were found in these lscolsmo multilayers. B unit, and this halfmetallic behavior can be maintained for larger strains. 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. Half metals are materials characterized by spin dependent band structures that exhibit properties of both insulators and metals.
It exhibits a secondorder paramagneticferromagnetic phase transition with tc 174 k. 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. Spinpolarized tunneling in nimnsbal 2 o 3 al junctions showed p of 28%, contrary to the predicted value of 100%. The band structure calculation shows that co2cral is a true halfmetallic ferromagnet with a magnetic moment. In the crystal, the a sites are occupied by lanthanum and strontium atoms, and the b sites are occupied by the smaller manganese atoms. A spin triplet supercurrent through the halfmetallic.
Our results highlight a new promising graphenelike half metallic ferromagnetic material for. 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. We have investigated the critical behavior of a shanditetype halfmetal ferromagnet co3sn2s2. 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.
The firstprinciple calculation within densityfunctional theory is used to investigate the hypothetical zincblende structured vbi. We will use the general gradient approximation method gga and. A new class of halfmetallic ferromagnets is found in the rutile structure. B unit, and this half metallic behavior can be maintained for larger strains.
Pdf halfmetallic ferromagnets and spin gapless semiconductors. Memory and spin injection devices involving half metals. This work reports on a spectroscopic investigation of thin co 2 mnsi films as they are used as electrodes in magnetic tunnel junctions. Using the korringakohnrostoker method kkr combined with the coherent potential approximation in the framework of firstprinciple calculations, we study the half metallic ferromagnetic. Charge dynamics in the halfmetallic ferromagnet cro 2 by. A spin metaloxidesemiconductor fieldeffect transistor. Xray diffraction and rutherford back scattering experiments indicated that the deposited nimnsb exhibited the desired structure and composition. Using the general expression, we next give the intuitive explanation about the amr effect 3. Effect of 0001 strain on the electronic and magnetic. Many of the known examples of halfmetals are oxides, sulfides, or heusler alloys in halfmetals, the valence band. The band structure calculation shows that co2cral is a true half metallic ferromagnet with a magnetic moment. Anisotropic magnetoresistance effects in fe, co, ni, fe4n. The sign in each parenthesis represents the sign of the amr ratio observed experimentally. Halfmetals are materials characterized by spin dependent band structures that exhibit properties of both insulators and metals.
The halfmetallic nature of zb tite exists within a wide range of lattice constant. Ferromagnetinsulatorferromagnet tunneling with one half. A rutile structure halfmetallic ferromagnet 368 vi. New bandgap measurement technique for a halfmetallic. The zb tite may be epitaxially grown on cdte substrate.
Exchange coupling of a perpendicular ferromagnet to a halfmetallic compensated ferrimagnet via a thin hafnium interlayer. 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. In the crystal, the a sites are occupied by lanthanum and strontium atoms, and the b sites are occupied by. Electronic structure of the halfmetallic ferromagnet kcrse2. Study of co2mnal heusler alloy as half metallic ferromagnet article pdf available in indian journal of physics 846. Direct evidence for a halfmetallic ferromagnet nature. Depthresolved resonant inelastic xray scattering at a. In addition, we show that the negative amr ratio is a necessary condition for halfmetallic ferromagnets 2,3,5,6,7. Although all halfmetals are ferromagnetic or ferrimagnetic, most ferromagnets are not halfmetals. The halfmetallic heusler compound co 2 mnsi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. 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. Density functional theory based electronic structure calculations will be performed by using the fullpotential linear augmented plane wave fplapw. Spinresolved photoelectron spectroscopy of oxidic half. The ferromagnet we use, cro 2, is a socalled halfmetallic ferromagnet 6.
Spin injection devices made in thin film form are also suggested. Spintronics is a new and emerging field in nanotechnology, which has been evolving rapidly. 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. Its halfmetallicity could be maintained within a relatively wide range of. In addition, we show that the negative amr ratio is a necessary condition for half metallic ferromagnets 2,3,5,6,7. Charge dynamics in the halfmetallic ferromagnet cro2. University of groningen halfmetallic ferromagnets katsnelson.
In addition, we observe different depth distribution of the rixs excitations. Critical behaviors of halfmetallic ferromagnet co3sn2s2. 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. It has an integer magnetic moment of 1 b per unit cell and a spinpolarized band structure with a. 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. Direct measurement of the conduction electron spin polarization p in epitaxial nimnsb was performed to test the prediction of half metallicity in this material. In a magnetic weyl semimetal with broken timereversal symmetry, there are significant. Apart from a polarization value as close as possible to unity, halfmetals must have also other properties in order to be functional.
M sb shows the full moment at very low temperature but decays much faster than the bulk magnetization \m b \ upon heating. The halfmetallic characteristic of zb tite appears in 6. This means that kcrse2 is a halfmetallic ferromagnet. Further we also found that a moderate change of the lattice parameters does not change the halfmetallic ferromagnet hmf behavior for both materials. State of co and mn in halfmetallic ferromagnet co2mnsi. Study of co 2 mnal heusler alloy as half metallic ferromagnet. Half metallic ferromagnets and spin gapless semiconductors. The critical components beta, gamma, and delta determined using the. Nonquasiparticle states in the halfmetallic ferromagnet nimnsb l. Using firstprinciples calculations within generalized gradient approximation, the electronic and magnetic properties of zinc blende zb crpmnp superlattice. 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. Aonedimensional halfmetallic ferromagnet volodymyr v. It aims to exploit the spin degree of freedom in order to realise advanced electronic devices.
Our results highlight a new promising graphenelike halfmetallic ferromagnetic material for. Charge dynamics in the halfmetallic ferromagnet cro 2. We suggest memory and spin injection devices fabricated with half metallic materials and based on the anomalous hall effect. 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. Thus, the electronic properties of this organometallic wire. We will use the general gradient approximation method gga and local density approximation.
Large intrinsic anomalous hall effect in halfmetallic. Direct evidence for a halfmetallic ferromagnet article pdf available in nature 3926678. Highlights the nm nias is the ground state of tite and fm zb phase becomes stable at. The electronic transport is metallic for the spinup electrons, while it is. The magnetization m versus applied magnetic field h isotherm. Ferromagnetinsulatorferromagnet fmifm tunnel junctions were prepared with one ferromagnet being nimnsb, a compound predicted by degroot et al. Halfmetallic ferromagnetism in the zincblende tite. 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. These devices do not need any external magnetic field but make use of their own magnetization. We suggest memory and spin injection devices fabricated with halfmetallic materials and based on the anomalous hall effect. The halfmetallic ferromagnet has 100% spin polarization for the conduction electrons, and thus it offers. Cro2 predicted as a halfmetallic ferromagnet iopscience.
Spinpolarized tunneling in a halfmetallic ferromagnet. The investigated films exhibit a remanent inplane magnetization with a. Ferromagnet insulator ferromagnet fmifm tunnel junctions were prepared with one ferromagnet being nimnsb, a compound predicted by degroot et al. 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. We have investigated the critical behavior of a shanditetype half metal ferromagnet co3sn2s2. Intuitive explanation of anisotropic magnetoresistance amr. The zb tite is a complete halfmetal with minority spin gap about 2. Magnetic properties at surface boundary of a halfmetallic. It has a perovskite based crystal structure, which has the general form abo 3. Local structural analysis of halfmetallic ferromagnet. Journal of magnetism and magnetic materials 2017, 433, 222226.
New bandgap measurement technique for a half metallic ferromagnet alhuwaymel, tariq fahad h 2015 new bandgap measurement technique for a half metallic ferromagnet. Intuitive explanation of anisotropic magnetoresistance. Half metallic ferromagnetism fm in singlecrystal ba0. 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. 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. Our calculations indicate that the zbtype vbi is predicted to be a true halfmetallic ferromagnet with a magnetic moment of 2.
Local structural analysis of halfmetallic ferromagnet cro2. Exchange interactions and critical temperatures in halfmetallic compounds 370 a. Robust halfmetallic ferromagnetism in cr 3 c 2 mxene. For the minorityspin direction the fermi level lies in a 1. The ferromagnet we use, cro 2, is a socalled half metallic ferromagnet 6. That is, the electrons responsible for the metallic behavior share the same spin. Schematic diagrams of the memory chips, in thin film and bulk crystal form, are presented. Halfmetallic ferromagnetism in the hypothetical zincblende. Study of co2mnal heusler alloy as half metallic ferromagnet.
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