Spin Injection Experiments from Half-Metallic Ferromagnets into Semiconductors: The Case of NiMnSb and (Ga,Mn)As

2005 ◽  
pp. 275-287
Author(s):  
Willem Van Roy
Keyword(s):  
Spin Injection ◽  
Half Metallic

scholarly journals Coherent manipulation of nuclear spins using spin injection from a half-metallic spin source

2015 ◽  
Vol 91 (14) ◽  
Author(s):  
Tetsuya Uemura ◽  
Takafumi Akiho ◽  
Yuya Ebina ◽  
Masafumi Yamamoto
Keyword(s):  
Spin Injection ◽  
Nuclear Spins ◽  
Half Metallic ◽  
Coherent Manipulation

Enhancing spin injection efficiency through half-metallic miniband conduction in a spin-filter superlattice

2016 ◽  
Vol 28 (5) ◽  
pp. 056003 ◽  
Author(s):  
Yi-Hang Yang ◽  
Lin Li ◽  
Fen Liu ◽  
Zhi-Wei Gao ◽  
Guo-Xing Miao
Keyword(s):  
Spin Injection ◽  
Spin Filter ◽  
Injection Efficiency ◽  
Half Metallic

Electronic Structure and Spin-Injection of Co-Based Heusler Alloy/ Semiconductor Junctions

2011 ◽  
Vol 470 ◽  
pp. 54-59
Author(s):  
Hiroyoshi Itoh ◽  
Syuta Honda ◽  
Junichiro Inoue
Keyword(s):  
Electronic Structure ◽  
Heusler Alloy ◽  
Spin Injection ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Growth Direction ◽  
Layer By Layer ◽  
Half Metallicity ◽  
Half Metallic ◽  
Layer Stacking

The electronic structures of Co-based Heusler alloys with nonstoichiometric atomic compositions as well as those at the interface of semiconductor junctions are investigated using first principles band calculations. It is shown that the electronic structure of a Co-based Heusler alloy is half-metallic, even for nonstoichiometric but Co-rich compositions, whereas the half-metallicity is lost for Co-poor compositions. It is also shown that magnetic moments at the interface of Co2MnSi/ Si junctions are sensitive to the growth direction and interface structure of the junctions. Efficient spin-injection into Si can be achieved by using a (111)-oriented Co-rich Heusler alloy and controlling the layer-by-layer stacking sequence at the interface.

Spin-injection device prospects for half-metallic Fe3O4:Al0.1Ga0.9As interfaces

2010 ◽  
Vol 108 (3) ◽  
pp. 034507 ◽  
Author(s):  
R. Mansell ◽  
J.-B. Laloë ◽  
S. N. Holmes ◽  
P. K. J. Wong ◽  
Y. B. Xu ◽  
...  
Keyword(s):  
Spin Injection ◽  
Injection Device ◽  
Half Metallic

scholarly journals COMPARATIVE STUDY OF SPIN INJECTION AND TRANSPORT IN Alq3 AND Co–PHTHALOCYANINE-BASED ORGANIC SPIN VALVES

SPIN ◽  
2014 ◽  
Vol 04 (02) ◽  
pp. 1440009 ◽  
Author(s):  
SAYANI MAJUMDAR ◽  
SUKUMAR DEY ◽  
HANNU HUHTINEN ◽  
JOHNNY DAHL ◽  
MARJUKKA TUOMINEN ◽  
...  
Keyword(s):  
Single Molecule ◽  
Giant Magnetoresistance ◽  
Chemical Reactivity ◽  
Spin Injection ◽  
Spin Valve ◽  
Spin Valves ◽  
Half Metallic ◽  
High Expectations ◽  
Spacer Layer ◽  
Spin Polarized

Recent experimental reports suggest the formation of a highly spin-polarized interface ("spinterface") between a ferromagnetic (FM) Cobalt ( Co ) electrode and a metal-phthalocyanine (Pc) molecule. Another report shows an almost 60% giant magnetoresistance (GMR) response measured on Co / H 2 Pc -based single molecule spin valves. In this paper, we compare the spin injection and transport properties of organic spin valves with two different organic spacers, namely Tris(8-hydroxyquinolinato) aluminum ( Alq 3) and CoPc sandwiched between half-metallic La 0.7 Sr 0.3 MnO 3 (LSMO) and Co electrodes. Alq 3-based spin valves exhibit clear and reproducible spin valve switching with almost 35% negative GMR at 10 K, in accordance with previous reports. In contrast, cobalt-pthalocyanine ( CoPc )-based spin valves fail to show clear GMR response above noise level despite high expectations based on recent reports. Investigations of electronic, magnetic and magnetotransport properties of electrode/spacer interfaces of LSMO/ CoPc / Co devices offer three plausible explanations for the absence of GMR: (1) CoPc films are strongly chemisorbed on the LSMO surface. This improves the LSMO magnetic properties but also induces local traps at the LSMO interface for spin-polarized charge carriers. (2) At the Co / CoPc interface, diffusion of Co atoms into the organic semiconductor (OS) layer and chemical reactivity between Co and the OS deteriorates the FM properties of Co . This renders the Co / CoPc interface as unsuitable for efficient spin injection. (3) The presence of heavy Co atoms in CoPc leads to large spin–orbit coupling in the spacer. The spin relaxation time in the CoPc layer is therefore considerably smaller compared to Alq 3. Based on these findings, we suggest that the absence of GMR in CoPc -based spin valves is caused by a combined effect of inefficient spin injection from FM contacts and poor spin transport in the CoPc spacer layer.

scholarly journals Coherent manipulation of nuclear spins using spin injection from a half-metallic spin source

2016 ◽  
Author(s):  
Tetsuya Uemura ◽  
Takafumi Akiho ◽  
Yuya Ebina ◽  
Masafumi Yamamoto
Keyword(s):  
Spin Injection ◽  
Nuclear Spins ◽  
Half Metallic ◽  
Coherent Manipulation

Materials and Device Design with ZnO-Based Diluted Magnetic Semiconductors

2001 ◽  
Vol 666 ◽  
Author(s):  
Kazunori Sato ◽  
Hiroshi Katayama-Yoshida
Keyword(s):  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Spin Injection ◽  
Wide Band ◽  
Ferromagnetic State ◽  
Hole Doping ◽  
Half Metallic ◽  
Practical Applications ◽  
Doped Zno ◽  
Diluted Magnetic

ABSTRACTWe propose a materials design to fabricate the transparent and half-metallic ferromagnets in V-, Cr-, Mn+hole, Fe-, Co-, and Ni-doped ZnO based upon ab initio electronic structure calculation. Mn-doped ZnO is anti-ferromagnetic spin glass state, however, it becomes half-metallic ferromagnets upon hole doping. The ferromagnetic state becomes more stable by electron doping in Fe-, Co- or Ni-doped ZnO. From the point of practical applications, it is feasible to realize the half-metallic ferromagnets with high Curie temperature, because n-type ZnO is easily available. We propose the design of new functional devices, such as spin-FET, photo-induced ferromagnets, and spin-injection devices using negative electron affinity in the wide band gap semiconductors.

scholarly journals Memory and Spin Injection Devices Involving Half Metals

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
M. Shaughnessy ◽  
Ryan Snow ◽  
L. Damewood ◽  
C. Y. Fong
Keyword(s):  
Thin Film ◽  
Spin Injection ◽  
Anomalous Hall Effect ◽  
Crystal Form ◽  
Metallic Materials ◽  
Half Metallic ◽  
Half Metals ◽  
Spin Polarized ◽  
Film Form ◽  
Made In

We suggest memory and spin injection devices fabricated with half-metallic materials and based on the anomalous Hall effect. Schematic diagrams of the memory chips, in thin film and bulk crystal form, are presented. Spin injection devices made in thin film form are also suggested. These devices do not need any external magnetic field but make use of their own magnetization. Only a gate voltage is needed. The carriers are 100% spin polarized. Memory devices may potentially be smaller, faster, and less volatile than existing ones, and the injection devices may be much smaller and more efficient than existing spin injection devices.

HIGH-FIELD HALL EFFECT AND BAND STRUCTURE OF HALF-METALLIC CrO2 FILMS

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3334-3337 ◽  
Author(s):  
S. M. WATTS ◽  
S. VON MOLNáR ◽  
M. JAIME
Keyword(s):  
Band Structure ◽  
Hall Effect ◽  
Carrier Transport ◽  
Structural Characteristics ◽  
Spin Injection ◽  
Chemical Vapor ◽  
Decomposition Methods ◽  
Band Model ◽  
Sign Reversal ◽  
Half Metallic

The Hall effect of (100)- and (110)-oriented films of the half-metallic ferromagnetic oxide CrO2, fabricated by both chemical vapor deposition and high pressure, thermal decomposition methods, has been examined in large magnetic fields up to 60 T. In all cases the Hall effect exhibits a sign reversal from positive to negative with increasing field, which we take as evidence for multi-band behavior. (110) films fabricated by both methods exhibit this sign reversal at relatively low fields. The data may be fit with a simple two-band model, which indicates the existence of highly mobile holes of p-like parentage, along with a much larger number of heavy, d-like electrons. In the (100) film the sign reversal is at much higher field. The parameters obtained from the fits allow us (with help from band structure calculations) to infer the band structure near the Fermi level and how it depends on sample strain and other structural characteristics. These details will be important for understanding carrier transport through interfaces such as for spin injection or other "spintronics" applications.

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