La0.7Sr0.3MnO3 Research Articles

Interfacial quantum interference effect and dual magnetoresistance in La0.7Sr0.3MnO3 thin films grown on (001) Si

Transmission electron microscope image and electronic transport of La0.7Sr0.3MnO3 (LSMO) films grown on (001) oriented Si using the sputtered pulsed plasma method confirmed the presence of around 8 nm thick, less dense, and highly resistive LSMO at the interface below the conducting phase. Thicker LSMO films, in addition to metal-insulator transition, show an anomaly around the Curie temperature in temperature-dependent resistivity and magnetoresistance (MR), which is a unique observation. The conduction in these LSMO films at temperatures below low-temperature resistivity minimum is dominated by Kondo-like scattering over electron–electron scattering, established using the phenomenological model. At 20 K, the maximum positive MR is ∼ 12% for the in-plane field, while it is ∼ 7.2% for the out-of-plane field. The maximum negative in-plane MR is found to be ∼ 42.5%, which becomes ∼ 30% when the orientation of the field changes to the out-of-plane direction. The two-dimensional field-dependent change in the magneto-conductance model evidenced the quantum interference effect (QIE). The existence of QIE is associated with magnetic scattering and scattering due to spin–orbit coupling. These results may be used to modulate the electrical properties of future electronic devices and can encourage scientists to explore the multi-functionalities of complex oxides grown on bare Si substrates.

Dimensionality engineering dependence of vertical magnetization shift and magnetic anisotropy evolution in manganite superlattices

The manganite superlattices consisting of a ferromagnetic La0.7Sr0.3MnO3 (LSMO) metal and a G-type antiferromagnetic SrMnO3 (SMO) insulator have been investigated in this work. Two very intriguing effects have been observed in these LSMO/SMO superlattices. The first one is the coexistence of the robust exchange bias and the evident vertical magnetization shift in the thicker superlattices. The second is the magnetic anisotropy variation from planar to perpendicular with increasing SMO layer thickness. These two novel phenomena have been confirmed by the electric transport anisotropy measurements and the microscopic magnetic domain switching images. Moreover, the X-ray linear dichroism experiments and first-principle calculations have revealed the orbital reconstruction dependence on the SMO layer thickness. It is noteworthy that the vertical magnetization shift and perpendicular magnetic anisotropy are usually observed in intrinsic out-of-plane magnetic easy axis materials such as SrRuO3-based heterostructures. However, the spins within LSMO films preferably orient towards the in-plane direction. Therefore, a new microscopic method for vertical magnetization shift and magnetic anisotropy manipulation has been developed, enabling the discovery of emergent phenomena as well as the control of the magnetic properties.

Enhanced low-field positive magnetoresistance and magnetic anisotropy in La0.7Sr0.3MnO3 films grown on (001) Si

Strong anisotropy is observed in the magnetization and magnetoresistance (MR) of a series of La0.7Sr0.3MnO3 (LSMO) films grown on (001) oriented Si using pulsed sputtering plasma. Magnetic anisotropy (MA) of LSMO films is in the order of 106 erg/cm3, comparable to or larger than that of the other heterostructures. Analysis using the Stoner-Wohlfarth model and the density functional theory (DFT) indicates that the crystalline and induced anisotropies are almost compensating with each other, and observed MA is of the same order of shape anisotropy. The rise in MA with the LSMO thickness is attributed to the shape anisotropy and interfacial spin reordering. These LSMO films exhibit positive and negative MR, even though the LSMO is well known for colossal negative MR. The 12.4 nm thick LSMO film shows a maximum ∼7 % in-plane low-field positive MR, which increases to ∼12 % for 20.0 nm thick LSMO, but the variation of out-of-plane positive MR is ∼ ± 0.8 %. The maximum in-plane positive MR occurs at ∼ ± 0.2 kG (switching field), which corresponds to the coercive field. In contrast, the out-of-plane positive MR switching field is relatively higher, ∼ ± 5 kG, 25 times larger than the in-plane switching field. The anisotropy in positive MR and its switching field is due to the strong MA, modulated by the charge transfer-induced interfacial exchange coupling strength, confirmed using the DFT. The MA and anisotropy in MR with the dual sign of MR are intriguing phenomena; their tunability could pave the way for advanced technology in magnetic devices.

Electrochemical characteristics of limiting current sensors with LSM-YSZ and LSM-CGO-YSZ composite electrodes

Limiting current gas sensors with Pt electrodes are widely used to detect gaseous species, such as O2, CO, HC, and NOx, from exhaust gases generated by the incomplete combustion of fossil fuels. In this study, aperture-type limiting current sensors were fabricated based on La0.8Sr0.2MnO3 (LSM)–yttria-stabilized zirconia (YSZ) and LSM–Gd0.1Ce0.9O2-d (CGO)–YSZ composites. The potential of these composites as alternative electrodes for O2 and CO sensing was evaluated. The composite electrodes exhibited current–voltage curves that are typical for limiting current sensors. LSM–CGO–YSZ registered higher limiting current values than those of the commercial Pt and LSM–YSZ electrodes in O2 and CO atmospheres. The formation of a resistive secondary La2Zr2O7 phase at the LSM/YSZ interface of LSM–YSZ deteriorates the electrochemical reaction and increases the polarization resistance of the electrode in the CO environment. The addition of CGO prevented the formation of the secondary phase, which lowered the ohmic and polarization resistances of LSM–CGO–YSZ compared to that of the LSM–YSZ composite. However, increasing the CGO concentration from 10 to 40 wt% weakened the adhesion of LSM and reduced the triple phase boundaries, which increased the electrode polarization resistance in both O2 and CO atmospheres.

Magnetic Field Enhancement in Critical Current and Possible Triplet Superconductivity in LSMO/YBCO/LSMO Heterostructures

The large superconducting critical current (Ic) in superconductors is an important property for applications, but unfortunately, it is easily suppressed in the presence of a magnetic field. The stronger the magnetic field the lower the Ic is the common response of superconductors. In this paper, we discovered a phenomenon that the Ic can be enhanced by a field-cooled process for the La0.67Sr0.33MnO3 (LSMO)/YBa2Cu3O7−δ (YBCO)/La0.67Sr0.33MnO3 (LSMO) trilayer system, in which the high-Tc-superconductor/oxide-ferromagnetic interface plays a crucial role. Three major factors based on a singlet superconducting picture, such as the difference in the work functions, the orbital hybridization, and the magnetic coupling between the induced Cu and Mn moments at the interface, decide the charge transfer and the capability of carrying maximum current. These factors can be preset by a field-cooling process with various field-cooled fields at a temperature higher than the superconducting transition temperature, Tc. While the system is field-cooled below Tc, we found that the competition between these factors and the responses of the interface may enhance or suppress the properties of the superconducting layer and finally gives rise to a maximum Ic at a specific field-cooled field. Moreover, we also observed that the Ic increases with the increase of the applied magnetic field for the sample with a thinner YBCO layer, which cannot be explained by these mechanisms based on singlet superconductivity and strongly implies the possible existence of triplet superconducting pairs at the interface and inside a ferromagnetic (FM) layer.

The Modulated Magnetic Domain Structure in the La0.67Sr0.33MnO3 Ferromagnetic Films by Strain Engineering

Novel magnetic domain structures attract much attention due to their potential applications in the high performance of spintronic devices. Herein, the magnetic domains of La0.67Sr0.33MnO3 (LSMO) thin films, which epitaxially grown on (100)-, (110)-, and (111)-oriented (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates, are systematically investigated. The (100)- and (110)-LSMO films show a stripe domain pattern. After in-plane magnetic field saturation, the direction of the stripe domains in (100)-LSMO no longer rotates with the change of magnetic field, while the stripe domains in (110)-LSMO rotate continuously. The (111)-LSMO films produce randomly distributed bubble-like magnetic domains, which gradually connect into strips with the increase of the external magnetic field, and the stability of the magnetic domain in (111)-LSMO is better than the ones in (100)- and (110)-LSMO under a magnetic field. In addition, it is found that with the increase of thickness, the random domains in (111)-LSMO films are gradually transformed into mazy domains. These phenomena can be understood by the regulable strain anisotropy and the magnetic anisotropy. Herein, an effective way is suggested to modify the magnetization anisotropy and magnetic domain because spin polarization depends strongly on the crystal surface orientation as well as epitaxial strain.

Characterisations of La-Sr-Mn-O (LSMO) Thin Film Fabricated by RF Sputtering

A revisited study of perovskite-based manganite La0.67Sr0.33MnO3 (LSMO) deposited onto corning-glass (CG) substrates is reported here. The LSMO films were fabricated with RF sputtering with different deposition times, varying from 60 to 180 min, resulting in films with thicknesses of 35.0–109.7 nm. Rietveld refinements of the XRD spectrum showed that the samples exhibited hexagonal structures with a space group of R-3c (167) and remained unmodified structures. Clusters of monolayer growth were observed from the morphologies of the films. Interestingly, the average particle size obtained with an AFM perceived an insignificant variation of 31.7–35.6 nm despite the film thickness increment. Optical, electrical and magnetic properties were studied, as particle-size variation usually has a notable contribution to changes in these properties. It was found that the optical band gap (Eg) was in direct variation with the deposition time due to enhanced thickness and surface roughness. The temperature dependence of the resistivity graph was fitted with the percolation model to obtain further enlightenment on the electrical transport in the films. Low-field magnetoresistance (LFMR) was observed for all samples. Ferromagnetic to paramagnetic transition was observed in the vicinity of all samples’ TC values.

Morphology control of volatile resistive switching in La0.67Sr0.33MnO3 thin films on LaAlO3 (001)

The development of in-memory computing hardware components based on different types of resistive materials is an active research area. These materials usually exhibit analog memory states originating from a wide range of physical mechanisms and offer rich prospects for their integration in artificial neural networks. The resistive states are classified as either non-volatile or volatile, and switching occurs when the material properties are triggered by an external stimulus such as temperature, current, voltage, or electric field. The non-volatile resistance state change is typically achieved by the switching layer’s local redox reaction that involves both electronic and ionic movement. In contrast, a volatile change in the resistance state arises due to the transition of the switching layer from an insulator to a metal. Here, we demonstrate volatile resistive switching in twinned LaAlO3 onto which strained thin films of La0.67Sr0.33MnO3 (LSMO) are deposited. An electric current induces phase transition that triggers resistive switching, close to the competing phase transition temperature in LSMO, enabled by the strong correlation between the electronic and magnetic ground states, intrinsic to such materials. This phase transition, characterized by an abrupt resistance change, is typical of a metallic to insulating behavior, due to Joule heating, and manifested as a sharp increase in the voltage with accompanying hysteresis. Our results show that such Joule heating-induced hysteretic resistive switching exhibits different profiles that depend on the substrate texture along the current path, providing an interesting direction toward new multifunctional in-memory computing devices.

Enhancing the performance of mixed-potential NO2 sensors by optimizing the micromorphology of La0.8Sr0.2MnO3 electrodes

La0.8Sr0.2MnO3 (LSMn) was prepared as a sensing electrode (SE) for mixed-potential type NO2 sensors, and the effects of porous micromorphology on sensing performance were studied. The results showed that the grain size of La0.8Sr0.2MnO3 and the pore size of the SEs were regulated by sintering time. The sensitivity of the sensors increased and then decreased as the pore size increased. Selectivity was optimized via the sintering time. Finally, a NO2 sensor with SEs sintered at 1100 °C for 2 h showed commercially viable performance at 550 °C. These results indicate that the regulation of porous LSMn SE by sintering time could be applied in mixed-potential type NO2 sensors and is therefore a candidate for the monitoring of high-temperature exhaust.

High-Performance Implantable Sensors based on Anisotropic Magnetoresistive La0.67Sr0.33MnO3 for Biomedical Applications.

We present the design, fabrication, and characterization of an implantable neural interface based on anisotropic magnetoresistive (AMR) magnetic-field sensors that combine reduced size and high performance at body temperature. The sensors are based on La0.67Sr0.33MnO3 (LSMO) as a ferromagnetic material, whose epitaxial growth has been suitably engineered to get uniaxial anisotropy and large AMR output together with low noise even at low frequencies. The performance of LSMO sensors of different film thickness and at different temperatures close to 37 °C has to be explored to find an optimum sensitivity of ∼400%/T (with typical detectivity values of 2 nT·Hz-1/2 at a frequency of 1 Hz and 0.3 nT·Hz-1/2 at 1 kHz), fitted for the detection of low magnetic signals coming from neural activity. Biocompatibility tests of devices consisting of submillimeter-size LSMO sensors coated by a thin poly(dimethyl siloxane) polymeric layer, both in vitro and in vivo, support their high suitability as implantable detectors of low-frequency biological magnetic signals emerging from heterogeneous electrically active tissues.

Manipulating the magnetic and electric transport properties of La0.7Sr0.3MnO3 epitaxial thin film through ionic liquid-gated technology

Reversible manipulation of magnetic and electric transport properties by electrical means in perovskite transition metal oxides is of paramount importance in modern condensed matter physics and generates promising application prospects in electronic devices. However, the conventional method of field-effect transistor structure presents a huge limitation due to its poor ability to modulate the exceedingly high carrier density of about 1014−1015 cm−2. In this study, La0.7Sr0.3MnO3 (LSMO) epitaxial thin films with tensile and compressive strain states were obtained by growth on different single-crystal substrates. Compared with the LSMO thin film under tensile strain, the compressed LSMO thin film possesses more oxygen vacancies, a higher resistance and a smaller magnetization. In addition, the structural phases, magnetic and electric transport properties in both LSMO thin films were also manipulated by the ionic liquid-gated method. The LSMO thin film under compressive strain shows easier access to the reversible control of the structural phase and magnetic & electrical transport properties than the LSMO thin film under tensile strain. The synergy of the above capabilities proves an effective and reversible route to manipulate the properties of perovskite transition metal oxides, providing tremendous potential in the design of multiple-state memories, neuromorphic transistors, and other multifunctional devices.

Key Parameters for Detectivity Improvement of Low Noise Anisotropic Magnetoresistive Sensors Made of La2/3Sr1/3MnO3 Single Layers on Vicinal Substrates

The current trend in magnetoresistive sensors development is to increase the sensitivity of single sensing elements by using multilayer structures and to design them into arrays. Such arrays are designed to compensate the excess low frequency noise of individual elements, which limits their magnetic resolution. Here, we report the modeling, design, and fabrication of single layer anisotropic magnetoresistive (AMR) sensors using low noise epitaxial La2/3Sr1/3MnO3 (LSMO) oxide thin films deposited on vicinal SrTiO3 substrates. The fabrication process is simple, and the operation of the sensor is based on a step-induced uniaxial magnetic anisotropy, described using the Stoner–Wohlfarth model. A coherent magnetization reversal process is observed by magneto-optical Kerr effect imaging. A good agreement between experimental data and the expected sensor response confirms the correct operation of the device. Three main fabrication parameters, namely the vicinal angle of the substrate, the deposition temperature, the thin film thickness, and their effects on film anisotropy field and device detectivity have been studied. Detectivity levels as low as 1.4 nT Hz–1/2 at 1 Hz and 240 pT Hz–1/2 in the white noise region are achieved with a single Wheatstone bridge element operating at 310 K. Compared to GMR and AMR sensors, these results are promising for further development and for their use as single layer LSMO low field AMR sensors, including applications as implantable biomedical devices.

Enhanced oxygen evolution reaction via the tunability of spin polarization and electronic states in a flexible van der Waals membranous catalyst.

The response of the magnetic field and strain engineering in an electrochemical process, such as the oxygen evolution reaction (OER), not only provides a strategy for enhancing catalytic performance through external fields and mechanical stress but also serves as a platform for revealing the functionality of multiple degrees of freedom in catalysts. The perovskite transition metal oxide (TMO) thin film with precise stoichiometry and lattice ordering enables atomic-level catalysis mechanisms in various electrochemical processes, thereby facilitating the design and engineering of promising catalysts. However, the perplexing dominance of spin in an OER process is still a puzzle due to the strong correlation between transition metal d and oxygen p orbitals. In this study, we utilized La0.7Sr0.3MnO3 (LSMO) manganite as a ferromagnetic OER catalyst, which was directly deposited onto a flexible mica substrate. By subjecting LSMO to a tensile stress, we observed an enhanced OER, and the OER performance of LSMO improved by 30% with a +0.2% strain due to the weakened chemisorption of Mn-O. Moreover, it has been observed that the OER performance can be improved by approximately 87%, while the overpotential can be reduced by around 22% through the combination of a 5 kOe magnetic field and +0.2% strain. The OER performance of LSMO changed by ∼153% under 4% strain and 5 kOe magnetic field. Our experiments indicate that the primary source of the observed magnetic response is derived from the triplet state of O2, in which spin-polarized d and oxygen p orbitals decrease the spin potential within OER. This study provides experimental evidence for understanding the spin degree and electronic state regulation in the OER process, thereby facilitating further design and engineering of flexible magnetic electrochemistry catalysts with promising potential.

Silicon based Bi0.9La0.1FeO3 ferroelectric tunnel junction memristor for convolutional neural network application.

Computing in memory (CIM) based on memristors is expected to completely solve the dilemma caused by von Neumann architecture. However, the performance of memristors based on traditional conductive filament mechanism is unstable. In this study, we report a nonvolatile high-performance memristor based on ferroelectric tunnel junction (FTJ) Pd/Bi0.9La0.1FeO3 (6.9 nm) (BLFO)/La0.67Sr0.33MnO3 (LSMO) on a silicon substrate. The conductance of this device was adjusted by different pulse stimulation parameter to achieve various synaptic functions because of ferroelectric polarization reversal. Based on the multiple conductance characteristics of the devices and the high linearity and symmetry of weight updating, image processing and VGG8 convolutional neural network (CNN) simulation based on the devices were realized. Excellent results of the image processing are demonstrated. The recognition accuracy of CNN offline learning reached an astonishing 92.07% based on Cifar-10 dataset. This provides a more feasible solution to break through the bottleneck of von Neumann architecture.

Enhanced Optical Response in Au Nanopillar/La0.67Sr0.33MnO3 Film Composites: Implications for Magnetooptical Devices

Metal oxide vertically aligned nanocomposite thin films have been of considerable interest for hot-carrier-based light harvesting and active plasmonic applications. Herein, we present femtosecond pump–probe spectroscopy studies on a nanocomposite thin film with plasmonic Au nanopillars vertically aligned in a ferromagnetic La0.67Sr0.33MnO3 (LSMO) matrix. Our measurements reveal that the carrier decay of Au/LSMO films qualitatively follows that of pure LSMO with a two-component relaxation. In the presence of Au nanopillars, the charge generation within the LSMO film is enhanced by a factor of ∼40, and the spin–lattice relaxation time associated with demagnetization is substantially decreased from 259.6 to 7.7 ps. The enhanced nonequilibrium dynamics and energy transfer between the lattice and spin system in the Au/LSMO films can be well modeled using an extended three-temperature model. These Au/LSMO thin films can be potentially useful in ultrafast photoelectric and magnetooptical applications.

Evaluation of Structural and Functional Properties of La0.6Sr0.4MnO3 Perovskite Prepared by the Fast Solution Combustion Approach

A series of La0.6Sr0.4MnO3 (LSM) perovskite was made using the rapid solution combustion method, which was calcined by varying the temperatures. In order to determine how the calcination temperature affected the nanopowders produced and calcined at various temperatures, their microstructural, morphological, compositional, optical, and electrical properties were analyzed using corresponding characterization tools. The XRD results showed the coexistence of the rhombohedral polymorphs R-3c and Pm-3m for the perovskite phase under a calcination temperature of 1400 °C, which were eliminated with increased calcination temperature. The average grain size was found to increase with increasing calcination temperature. The EDS analysis showed better agreement of the stoichiometry with the theoretical composition. The apparent porosity decreased with increasing temperature due to the coalescence of sintering pores. The sample obtained after calcination at 1500 °C showed 10.3% porosity. The hardness also improved with increasing calcination temperature and reached a maximum value of 0.4 GPa, which matched the bulk density. A similar trend was observed in the resistivity studies as a function of temperature, and all the samples exhibited a low resistivity of ~1.4 Ω·cm in the temperature range of 500–600 °C. The optical characterization showed broad absorption at 560–660 nm and bandwidth values between 3.70 and 3.95 eV, according to the applied heat treatment.

Effect of annealing temperature on resistive switching behavior of Al/ La0.7Sr0.3MnO3 /LaNiO3 devices

La0.7Sr0.3MnO3 (LSMO)/LaNiO3 (LNO) thin films were deposited successively on Si single crystal by the sol-gel method. The bipolar resistive switching (RS) behavior was studied in Al/LSMO/LNO devices. Obvious current hysteresis was observed, the set (reset) voltage and resistance ratio were modulated by the annealing temperature of LSMO thin films. At the annealing temperature of 750 °C, good endurance and retention performance were obtained in the memory device. According to the fitting results of I–V curves, based on Schottky emission model, the conduction mechanisms of Al/LSMO/LNO devices were discussed. Our results may give a valuable insight on developing perovskite-type rare earth manganese oxide.

Strain- and thickness-dependent magnetic properties of epitaxial La0.67Sr0.33CoO3/La0.67Sr0.33MnO3 bilayers

Magnetic properties and interfacial phenomena of epitaxial perovskite oxides depend sensitively on parameters such as film thickness and strain state. In this work, epitaxial La0.67Sr0.33CoO3 (LSCO)/La0.67Sr0.33MnO3 (LSMO) bilayers were grown on NdGaO3 (NGO) and LaAlO3 (LAO) substrates with a fixed LSMO thickness of 6 nm, and LSCO thickness (tLSCO) varying from 2 to 10 nm. Soft x-ray magnetic spectroscopy revealed that magnetically active Co2+ ions that strongly coupled to the LSMO layer were observed below a critical tLSCO for bilayers grown on both substrates. On LAO substrates, this critical thickness was 2 nm, above which the formation of Co2+ ions was quickly suppressed leaving only a soft LSCO layer with mixed valence Co3+/Co4+ ions. The magnetic properties of both LSCO and LSMO layers displayed strong tLSCO dependence. This critical tLSCO increased to 4 nm on NGO substrates, and the magnetic properties of only the LSCO layer displayed tLSCO dependence. A non-magnetic layer characterized by Co3+ ions and with a thickness below 2 nm exists at the LSCO/substrate interface for both substrates. The results contribute to the understanding of interfacial exchange spring behavior needed for applications in next generation spintronic and magnetic memory devices.

(Invited) Effect of Atomic-Scale Surface Overcoat By Atomic Layer Deposition on Dopant Segregation of Perovskite Cathodes

Intense research has been performed to advance the solid oxide cell (SOC) technology because of their excellent efficiency for clean energy conversion and storage, but the lack of long-term durability, particularly of perovskite (ABO3)-based air electrodes, is currently the main technological bottleneck for wider commercial adoption. Long-term durability of SOC air electrodes has been mainly hampered by surface segregation of A-site dopant and morphological agglomeration. Since a deposition of an atomically thin oxide has proven to be highly effective in suppressing electrode agglomeration, a successful suppression of dopant segregation with the same approach will enhance the durability of air electrodes significantly by killing two birds with one stone. In the previous study [1], we demonstrated the effectiveness of an atomic scale overcoat in suppressing particle agglomeration. In this presentation, we demonstrate that even a few angstroms of metal oxide overcoat by atomic layer deposition (ALD) affects the behavior of Sr segregation in the underlying La0.8Sr0.2MnO3 (LSM) electrode significantly. By leveraging angle-resolved X-ray photoelectron spectroscopy (ARXPS), we provide a quantitative analysis of the relative atomic concentration on both the very surface and bulk of the electrode. Compared to bare LSM electrodes, those with 2 – 3 Å ALD overcoat show relatively high resistivity against Sr segregation when exposed to of 750 °C for 250 h. Particularly, an oxide overcoat with multi-valent cations (CeO2 and TiO2) tends to suppress Sr segregation effectively and even drive Sr species back into the bulk of LSM while an overcoat with single valent cations (ZrO2 and Y2O3) exhibits little effect on Sr segregation. It was further demonstrated that the segregation behavior is nicely aligned with the electrode performance; those coated with CeO2 and TiO2 showed better thermal stability in terms of polarization resistance. Based upon the time evolution of Sr content, cationic valence states, and oxygen defect concentration in the vicinity of surface, we conjecture that the amount of oxygen defects formed by the overcoat and the resulting chemical potential gradient at the interface between the overcoat underlying LSM surface plays a pivotal role in the Sr segregation behavior. The authors acknowledge the support from National Science Foundation (DMR 1753383) and NASA MIRO program (NNX15AQ01A).

Modeling of Spin Transport in Hybrid Magnetic Tunnel Junctions for Magnetic Recording Applications

We have demonstrated modeling of phonon and defect-induced spin relaxation length (LS) in Fe3O4 and organic semiconductor (OSC) Alq3. LS of Alq3 decreases with enhanced disorder and film thickness at a low film width regime. Exponential change of LS at low width regime is found for Alq3 which is, however, absent for Fe3O4 indicating comparable spin-dependent scattering and LS in Fe3O4. LS also decreases with spin-flip probability both for Alq3 and Fe3O4. Voltage-dependent tunnel magnetoresistance (TMR) response in Fe3O4/Alq3/Co and La0.7Sr0.3MnO3 (LSMO)/Alq3/Co hybrid magnetic tunnel junction (MTJ) devices has been attributed to modified spin filter effect across magnetic/OSC junction at high bias regime. TMR reduction with Alq3 thickness for Fe3O4 device has been attributed to spin relaxation at the organic spacer layer. A low bias peak from differential TMR indicates spin-polarized injection for both MTJ devices. Enhanced in-plane spin transfer torque for both MTJ is associated with modified spin filtering at magnetic/OSC junctions. Lower TMR signal for LSMO device indicates reduced tunneling and enhanced carrier injection across the OSC, which is also supported by the band structure profile. The TMR response observed from simulation results matches well with previously reported experimental results. Higher TMR response for Fe3O4 device indicates the possibility of device employment in room temperature magnetic recording applications.