Room-temperature magnetoresistance in organic spin-valves based on a Co2MnSi Heusler alloy

Kawasugi, Yoshitaka; Ujino, Tomohiro; Tada, Hayato

doi:10.1016/j.orgel.2013.09.002

Cited by 21 publications

(18 citation statements)

References 18 publications

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“…It was found that the bias voltage, V 1/2 at which the MR ratio reduces to the half of its maximum, is considerably larger in the DOSVs (about 0.7 V) than in the conventional OSVs (about 0.03 V). Although the MR magnitude of the conventional OSVs starts with a larger magnitude at a lower bias, it decays faster than that of DOSVs at high bias, and usually vanishes at the bias above 1 V. This relatively fast decaying MR has also been found in MTJ [21]. The MR in the single OSV becomes smaller than MR in DOSVs at bias voltages beyond the bias window, (50 mV, À100 mV), marked by two vertical dash lines in Fig.…”

Section: Bias Voltage Dependence Of Mr In Dosvsmentioning

confidence: 52%

“…1 spacers. This structure has been widely studied in the modified magnetic tunnel junction (MTJ), namely double-layer MTJ (DMTJ) where the MR magnitude was found to be relatively weak bias voltage dependence [21]. We found that the MR in the DOSVs is still measurable at an operation voltage as large as 6 V. This implies that the injected spin polarization in this device structure is enhanced at large applied voltage in comparison to conventional OSVs.…”

Section: Introductionmentioning

confidence: 82%

“…However, P 1 strongly reduces at temperature higher than 200 K [5]. The top Co electrode with P 2 $ 30% has the thickness dependent magnetic coercivity, and normally the thicker Co layer possesses the smaller magnetic coercivity [21]. It is possible to switch the relative magnetizations of the ferromagnetic electrodes between parallel and anti-parallel alignments, upon sweeping the external magnetic field, B. Consequently, there might be eight different states for the spin polarization configuration as the result of the spin polarization permutation from three magnetic layers in DOSVs, compared to four states in the conventional OSVs.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, the OSV shows only four spin polarization states leading two different resistance states. The DOSV is not simply considered as two individual OSVs in series as pointed out by Montaigne et al [21]. In addition, since the amorphous Co material has spin diffusion length of about 36 nm [29], the middle Co layer with 3 nm thickness does not cause a large spin loss in the DOSV.…”

Section: Mr Response Of Dosvs Versus Single Osvsmentioning

confidence: 99%

“…Remarkably, the MR response in OSVs has been found up to 300% at relatively low applied voltage and cryogenic temperature, but almost absent at room temperature in those devices [13,[16][17][18]. Recently, organic spintronics field has regained its momentum by several demonstrations of large and stable MR at room temperature, promising for the possible organic spintronic applications [19][20][21]. However, the MR seriously decays at large applied voltages and almost disappears at above 1 V bias voltage [4,13,22].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Large magnetoresistance at high bias voltage in double-layer organic spin valves

Liang

Geng

Zhang

et al. 2015

Organic Electronics

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Section: Bias Voltage Dependence Of Mr In Dosvsmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

Section: Mr Response Of Dosvs Versus Single Osvsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Large magnetoresistance at high bias voltage in double-layer organic spin valves

Liang

Geng

Zhang

et al. 2015

Organic Electronics

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Engineering of Spin Injection and Spin Transport in Organic Spin Valves Using π‐Conjugated Polymer Brushes

Geng

Roy

Zhao

et al. 2016

Adv Funct Materials

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Charge transport in amorphous organic semiconductors is governed by carriers hopping between localized states with small spin diffusion length. Furthermore, the interfacial resistance of organic spin valves (OSVs) is poorly controlled resulting in controversial reports of the magnetoresistance (MR) response. Here, surface‐initiated Kumada transfer polycondensation is used to covalently graft π‐conjugated poly(3‐methylthiophene) brushes from the La0.67Sr0.33MnO3 (LSMO) bottom electrode. The covalent attachment along with the brush morphology allows control over the LSMO/brush interfacial resistance and large spacer mobility. Remarkably, with 15 nm brush spacer layer, an optimum MR effect of 70% at cryogenic temperatures and a MR of 2.7% at 280 K are observed. The temperature dependence of the MR is nearly an order of magnitude weaker than that found in control OSVs made from spin‐coated poly(3‐hexylthiophene). Using a variety of different brush layer thicknesses, the thickness‐dependent MR at 20 K is investigated. A spin diffusion length of 17 nm at −5 mV junction voltage rapidly increased to 48.4 nm at −260 mV.

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Organic Spin Valves: A Review

Devkota

Geng

Subedi

et al. 2016

Adv Funct Materials

108

106

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accelerated impressively and advanced to a range of materials and a number of techniques to verify the successful injection and transport of the SP carriers. [ 1,2,10,11 ] The effect has been realized in a variety of materials combinations such as FM fi lms, FM/anti-FM coupled layers, or FM semiconductors as the injection/detection electrodes and the metals, superconductors, inorganic semiconductors, organic semiconductors, and insulators including ferroelectric and topological insulators as the spacers. [ 1,2,[12][13][14][15][16][17][18] The GMR effect was extensively studied using non-magnetic metallic interlayer and its applications such as electric switching, magnetic recording, and sensors were suggested and employed. [ 1,2,16 ] However, all-metallic spintronic devices imposed restrictions in applications as they are characterized by short spin relaxation time (≈picosecond) and are not suitable for coherent spin manipulation. [ 1,2,19 ] To overcome these limitations, the spintronics community caught its attention towards hybrid devices with semiconductors (SCs) sandwiched in between the FM layers and continued advancing to a range of semiconducting materials. [ 2,14,[20][21][22] The organic semiconductors (OSCs) are among the youngest members of the spacer materials and were fi rst tested in the spintronic devices only about a decade ago. Nevertheless, OSC devices have been of continuously advancing research topics over the past three decades for their rich physics, fl exible chemi stry, cost effi ciency, and potential applications in new generations of electronic devices including organic light emitting diodes (OLEDs), [23][24][25] organic solar cells, [ 26,27 ] and organic fi eld effect transistor. [ 28,29 ] In fact, OLEDs have already revolutionized the modern display industry and spin-dependent devices such as organic spin valves (OSVs), OLED-based magnetic sensors, and spin-OLEDs are under intensive study to achieve their new avenues. [30][31][32] This increasing interest on organic electronics is for their several distinctions over inorganic counterparts. [19][20][21]33,34 ] Electronically, the band theory explains the electric transport in inorganic SCs while charge hopping is the main transport mechanism in the OSCs with much smaller carrier mobility. This is a favorable condition for large electron-hole pair recombination without the need of using a p-n junction structure. [23][24][25] Spintronically, the inorganic SCs contain heavy atoms giving rise to a large spin-orbit coupling (SOC), which is a response of the electron spin degree of freedom to its orbital environment. The strength of the SOC in solids depends upon the nature of orbital wave functions of electrons and the materials structure. [ 35 ] In case of hydrogenic wave-function-like electrons (s-orbital electrons), it is Organic spintronics is an emerging and potential platform for future electronic devices. Signifi cant progress has been made in understanding the spin injection, manipulation, and detection in organic spin valves in the p...

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Room-temperature magnetoresistance in organic spin-valves based on a Co2MnSi Heusler alloy

Cited by 21 publications

References 18 publications

Large magnetoresistance at high bias voltage in double-layer organic spin valves

Large magnetoresistance at high bias voltage in double-layer organic spin valves

Engineering of Spin Injection and Spin Transport in Organic Spin Valves Using π‐Conjugated Polymer Brushes

Organic Spin Valves: A Review

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