Half-Metallic Ferromagnetic Oxides

MRS Bulletin ◽  
2003 ◽  
Vol 28 (10) ◽  
pp. 720-724 ◽  
Author(s):  
J.M.D. Coey ◽  
C.L. Chien
Keyword(s):  
Structural Defects ◽  
Point Contacts ◽  
Counter Electrodes ◽  
Half Metallicity ◽  
Polarized Electrons ◽  
Oxide Semiconductors ◽  
Spintronic Devices ◽  
Single Spin ◽  
Half Metals ◽  
Increasing Temperature

AbstractHalf-metals are unusual ferromagnets that have electrons at the Fermi level in a single spin state, either spin up or spin down. Of potential interest as sources and analyzers of polarized electrons in spintronic devices, they are usually identified from spin-dependent band-structure calculations. We present a classification scheme for half-metals and then discuss methods for measuring spin polarization based on point contacts or tunnel junctions with ferromagnetic or superconducting counter electrodes. Oxide examples include CrO2, the best-studied half-metal. The half-metallicity tends to be destroyed by increasing temperature and by structural defects. The half-metals that currently offer the best prospects for spintronics applications are those with the highest Curie temperatures, such as magnetite, Fe3O4, and perhaps oxide semiconductors such as Co-doped ZnO.

Nonvolatile electrical control of 2D Cr2Ge2Te6 and intrinsic half metallicity in multiferroic hetero-structures

Nanoscale ◽  
2021 ◽  
Author(s):  
Asif Ilyas ◽  
Shuling Xiang ◽  
Miaogen Chen ◽  
Muhammad Yar Khan ◽  
Hua Bai ◽  
...  
Keyword(s):  
Van Der Waals ◽  
Two Dimensional ◽  
Half Metallicity ◽  
Spintronic Devices ◽  
Electrical Control

The electrical control of two-dimensional (2D) van der Waals ferromagnets is a step forward for the realization of spintronic devices.

Ferromagnetic Dirac Half-Metallicity in Transition Metal Embedded Honeycomb Borophene

2021 ◽  
Author(s):  
Yanxia Wang ◽  
Xue Jiang ◽  
Yi Wang ◽  
Jijun Zhao
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Valence Electron ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Next Generation ◽  
Half Metallicity ◽  
Counting Rule ◽  
Spintronic Devices ◽  
Electron Counting

Exploring two-dimensional (2D) ferromagnetic materials with intrinsic Dirac half-metallicity is crucial for the development of next-generation spintronic devices. Based on first-principles calculations, here we propose a simple valence electron-counting rule...

scholarly journals Weyl fermions, Fermi arcs, and minority-spin carriers in ferromagnetic CoS2

2020 ◽  
Vol 6 (51) ◽  
pp. eabd5000
Author(s):  
Niels B. M. Schröter ◽  
Iñigo Robredo ◽  
Sebastian Klemenz ◽  
Robert J. Kirby ◽  
Jonas A. Krieger ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Half Metallicity ◽  
Spintronic Devices ◽  
Topological Materials ◽  
Fermi Arcs ◽  
Half Metal ◽  
Minority Spin ◽  
Electron Pocket

Magnetic Weyl semimetals are a newly discovered class of topological materials that may serve as a platform for exotic phenomena, such as axion insulators or the quantum anomalous Hall effect. Here, we use angle-resolved photoelectron spectroscopy and ab initio calculations to discover Weyl cones in CoS2, a ferromagnet with pyrite structure that has been long studied as a candidate for half-metallicity, which makes it an attractive material for spintronic devices. We directly observe the topological Fermi arc surface states that link the Weyl nodes, which will influence the performance of CoS2 as a spin injector by modifying its spin polarization at interfaces. In addition, we directly observe a minority-spin bulk electron pocket in the corner of the Brillouin zone, which proves that CoS2 cannot be a true half-metal.

scholarly journals Electronic and Magnetic Properties of Li1.5Mn0.5As Alloys in the Cu2Sb Structure

2013 ◽  
Vol 702 ◽  
pp. 231-235 ◽  
Author(s):  
C.Y. Fong ◽  
Liam Damewood ◽  
L.H. Yang ◽  
C. Felser
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Ab Initio ◽  
Lattice Constant ◽  
Magnetic Moments ◽  
The Other ◽  
Half Metallicity ◽  
Ionic Model ◽  
Half Metals ◽  
Ferromagnetic Metals

We investigated two formula-units of Li1.5Mn0.5As alloys, such as Li3MnAs2, in the Cu2Sb crystal structure using an ab-initio algorithm. By interchanging Mn with each Li located at different positions of the Li4As2unit cell, four separate alloys are formed. At the optimized lattice constant, two of these alloys are predicted to be ferromagnetic metals and the other two are half metals. The possibility of half metallicity in the first two is also explored. Both the modified Slater-Pauling-Kübler rule and the ionic model can characterize the magnetic moments of the half metals.

Thermoelectric Transport Properties of Individual Bismuth Nanowires

2001 ◽  
Vol 691 ◽  
Author(s):  
Stephen B. Cronin ◽  
Yu-Ming Lin ◽  
Oded Rabin ◽  
Marcie R. Black ◽  
Gene Dresselhaus ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Point Contacts ◽  
Large Spread ◽  
Thermoelectric Transport Properties ◽  
Bismuth Nanowires ◽  
Increasing Temperature ◽  
Magneto Resistance

ABSTRACTWe developed a method for making 4-point contacts to Bi nanowires with a thick oxide coat using a combination of lithographic and focused ion beam (FIB) techniques. The resistivity of Bi nanowires with diameters in the range 70-200nm is found to increase with decreasing wire diameter. In contrast to bulk Bi, the temperature dependence of the resistivity is found to decrease monotonically with increasing temperature. The results are explained on the basis of increased scattering in the nanowire and the known temperature dependence of the electronic properties of bulk Bi. A large magneto-resistance was also measured, indicating a high crystalline quality of the nanowires. A large spread in the measured values of the resistivity indicates significant systematic error in the measurement technique. Possible sources for error are discussed.

Computational search for two-dimensional intrinsic half-metals in transition-metal dinitrides

2017 ◽  
Vol 5 (3) ◽  
pp. 727-732 ◽  
Author(s):  
Junyan Liu ◽  
Zhifeng Liu ◽  
Tielei Song ◽  
Xin Cui
Keyword(s):  
Transition Metal ◽  
First Principles ◽  
Two Dimensional ◽  
Half Metallicity ◽  
2D Material ◽  
Half Metals ◽  
Computational Search

A promising 2D material (1T-TaN2 monolayer) with intrinsic half-metallicity and ferromagnetism has been characterized by a first-principles computational search.

scholarly journals Addressing single spin crossover molecules in a two-dimensional monolayer

2021 ◽  
Author(s):  
Yongfeng Tong ◽  
Massine Kelaï ◽  
Kaushik Bairagi ◽  
Vincent Repain ◽  
Jérôme Lagoute ◽  
...  
Keyword(s):  
Spin State ◽  
Single Molecule ◽  
Spin Crossover ◽  
Cooperative Behaviour ◽  
Spintronic Devices ◽  
Single Spin ◽  
Elastic Interactions ◽  
Molecular Spin ◽  
External Stimuli ◽  
At Will

Abstract Bistable spin-crossover molecules are particularly interesting to the development of innovative electronic and spintronic devices as they present two spin states that can be controlled by external stimuli. In this purpose, being able to switch at will the spin state of a single molecule in a dense molecular array is a key milestone. However, the elastic interactions between the molecules favour more cooperative behaviour where patches of neighbouring molecules switches simultaneously. We demonstrate here that the interaction of iron II spin-crossover molecules with a metallic substrate can strongly reduce their cooperative behaviour until addressing independently single molecular spin state. Mechanoelastic model is able to reproduce well such findings.

scholarly journals Large ultrafast-modulated Voigt effect in noncollinear antiferromagnet Mn3Sn

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
H. C. Zhao ◽  
H. Xia ◽  
S. Hu ◽  
Y. Y. Lv ◽  
Z. R. Zhao ◽  
...  
Keyword(s):  
High Speed ◽  
Linear Dichroism ◽  
Laser Pulses ◽  
Time Resolved ◽  
Spin Configuration ◽  
Ultrafast Laser Pulses ◽  
Spintronic Devices ◽  
Wide Range ◽  
Kerr Angle ◽  
Increasing Temperature

AbstractThe time-resolved magneto-optical (MO) Voigt effect can be utilized to study the Néel order dynamics in antiferromagnetic (AFM) materials, but it has been limited for collinear AFM spin configuration. Here, we have demonstrated that in Mn3Sn with an inverse triangular spin structure, the quench of AFM order by ultrafast laser pulses can result in a large Voigt effect modulation. The modulated Voigt angle is significantly larger than the polarization rotation due to the crystal-structure related linear dichroism effect and the modulated MO Kerr angle arising from the ferroic ordering of cluster magnetic octupole. The AFM order quench time shows negligible change with increasing temperature approaching the Néel temperature (TN), in markedly contrast with the pronounced slowing-down demagnetization typically observed in conventional magnetic materials. This atypical behavior can be explained by the influence of weakened Dzyaloshinskii–Moriya interaction rather than the smaller exchange splitting on the diminished AFM order near TN. The temperature-insensitive ultrafast spin manipulation can pave the way for high-speed spintronic devices either working at a wide range of temperature or demanding spin switching near TN.

scholarly journals The Electronic, Magnetic, Half-Metallic and Mechanical Properties of the Equiatomic Quaternary Heusler Compounds FeRhCrSi and FePdCrSi: A First-Principles Study

2018 ◽  
Vol 8 (12) ◽  
pp. 2370 ◽  
Author(s):  
Liefeng Feng ◽  
Jiannan Ma ◽  
Yue Yang ◽  
Tingting Lin ◽  
Liying Wang
Keyword(s):  
First Principles ◽  
Mechanical Stability ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Half Metallicity ◽  
External Interference ◽  
Half Metals ◽  
Wide Range ◽  
Quaternary Heusler Alloys ◽  
Low Sensitivity

By using the first-principles method, the electronic structures and magnetism of equiatomic quaternary Heusler alloys FeRhCrSi and FePdCrSi were calculated. The results show that both FeRhCrSi and FePdCrSi compounds are ferrimagnets. Both compounds are half-metals and their half-metallicity can be maintained in a wide range of variation of the lattice constant under hydrostatic strain and c/a ratio range under tetragonal distortion, implying that they have low sensitivity to external interference. Furthermore, the total magnetic moments are integers, which are typical characteristics of half-metals. The calculated negative formation energy and cohesive energy indicate that these two alloys have good chemical stability. Furthermore, the value of the elastic constants and the various moduli indicate the mechanical stability of these two alloys. Thus, FeRhCrSi and FePdCrSi are likely to be synthesized in the experiment.

High Curie temperature and intrinsic ferromagnetic half-metallicity in two-dimensional Cr3X4 (X = S, Se, Te) nanosheets

2019 ◽  
Vol 4 (4) ◽  
pp. 859-866 ◽  
Author(s):  
Xiwen Zhang ◽  
Bing Wang ◽  
Yilv Guo ◽  
Yehui Zhang ◽  
Yunfei Chen ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Exchange Interaction ◽  
Double Exchange ◽  
High Curie Temperature ◽  
Two Dimensional ◽  
Half Metallicity ◽  
Double Exchange Interaction ◽  
Half Metals

High Curie temperature in two-dimensional ferromagnetic half-metals is attainable via double-exchange interaction.

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