The magnetic domain of a Co/Pt thin film that was grown on a crystal (011) Pb(Mg
1/3
Nb
2/3
)O
3
–PbTiO
3
(PMN–PT) substrate was regulated by an electric field at room temperature (RT). The magnetic ...hysteresis loops and magnetic domain state were recorded by means of the magnetic optical Kerr effect (MOKE). In the unpoled state, magnetic domain wall propagation was observed directly under a fixed perpendicular magnetic field. In addition, the change of the coercive field under various electric fields was consistent with the change of strain curve—attributed to the piezostrain effect in (Co/Pt)/PMN–PT heterostructure. Moreover, the magnetic domain that was driven by the electric field exhibited a similar behavior. Electric-field control of magnetic domain was demonstrated by exploiting piezostrain-mediated magnetoelectric coupling in ferromagnetic/ferroelectric heterostructures with perpendicular magnetic anisotropy, which is promising for designing of future spin-transfer torque magnetoresistive random access memory devices.
Objective:
To investigate the role of prediction microvascular invasion (mVI) in hepatocellular carcinoma (HCC) by
18
F-FDG PET image texture analysis and hybrid criteria combining PET/CT and ...multi-parameter MRI.
Materials and methods:
Ninety-seven patients with HCC who received the examinations of MRI and
18
F-FDG PET/CT were retrospectively included in this study and were randomized into training and testing cohorts. The lesion image texture features of
18
F-FDG PET were extracted using MaZda software. The optimal predictive texture features of mVI were selected, and the classification procedure was conducted. The predictive performance of mVI by radiomics classier in training and testing cohorts was respectively recorded. Next, the hybrid model was developed by integrating the
18
F-FDG PET image texture, metabolic parameters, and MRI parameters to predict mVI through logistic regression. Furthermore, the diagnostic performance of each time was recorded.
Results:
The
18
F-FDG PET image radiomics classier showed good predicted performance in both training and testing cohorts to discriminate HCC with/without mVI, with an AUC of 0.917 (95% CI: 0.824–0.970) and 0.771 (95% CI: 0.578, 0.905). The hybrid model, which combines radiomics classier, SUVmax, ADC, hypovascular arterial phase enhancement pattern on contrast-enhanced MRI, and non-smooth tumor margin, also yielded better predictive performance with an AUC of 0.996 (95% CI: 0.939, 1.000) and 0.953 (95% CI: 0.883, 1.000). The differences in AUCs between radiomics classier and hybrid classier were significant in both training and testing cohorts (DeLong test, both
p
< 0.05).
Conclusion:
The radiomics classier based on
18
F-FDG PET image texture and the hybrid classier incorporating
18
F-FDG PET/CT and MRI yielded good predictive performance, which might provide a precise prediction of HCC mVI preoperatively.
Introduction:
Although electric field mediated the magnetic anisotropy in ferromagnetic/ferroelectric structure have an intense report, the angle between the magnetic uniaxial anisotropy and strain ...anisotropy influencing the rearrangement of the magnetic moment has not well investigated.
Methods:
Keithley 2410 direct current power supply was used to provide voltage through the Cu wires. Static magnetic properties of CoZr layer were measured through VSM (MicroSense EV9). Dynamic magnetic properties were obtained by FMR (JEOL JES-FA 300 spectrometer, power of 1-mW, X-band at 8.969 GHz).
Results and Discussion:
Electric field-mediated, room-temperature magnetic anisotropy of CoZr/Pb(Mg
1/3
Nb
2/3
)O
3
–PbTiO3 (PMN–PT) structures, in which easy axis of CoZr layer along either direction of 01-1 or 100 of PMN–PT, was investigated. Measured with vibrating sample magnetometer, for 01-1 easy-axis direction sample, when an electric field was applied, these directions of easy axis and hard axis remains unchanged. However, for 100 easy-axis direction sample, these directions of easy axis and hard axis were changed obviously with applying electric field, attributable to the competition between magnetic uniaxial anisotropy of CoZr layer and piezostrain anisotropy of PMN-PT substrate. Nevertheless, change of the resonance magnetic field with electric field–measured by ferromagnetic resonance–exhibited non-volatile behavior, which possibly indicates magnon-driven magnetoelectric coupling existing in CoZr/PMN–PT structures.
The in-plane effective 90° magnetization rotation of Co2FeAl thin film grown on PMN-PT substrate induced by the electric field is investigated at room temperature.The magnetic hysteresis loops under ...different positive and negative electric fields are obtained,which reveals remanent magnetization can be mediated by the electric field.Moreover,under positive electric fields,the obvious 90° magnetization rotation can be observed,while remanent magnetization is nearly un-changed under negative electric fields.The result is consistent with the electric field dependence of effective magnetic field,which can be attributed to the piezostrain effect in Co2FeAl/PMN-PT structure.In addition,the piezostrain-mediated 90°magnetization rotation can be demonstrated by the result of resonance field changing with electric field in the measurement of ferromagnetic resonance,which is promising for the design of future multiferroic devices.
The anomalous Hall effect (AHE) in Co/Pt3 thin films with perpendicular magnetic anisotropy grown on Pb(Mg1/3Nb2/3)O3–Pb0.7Ti0.3O3 substrates is investigated under application of different electric ...fields at various temperatures. As the sweeping mode of application of the electric field changes from symmetric bipolar to asymmetric bipolar, the butterfly-like behavior of the resistivity vs electric field curves is converted into loop-like behavior, which is attributed to the piezostrain effect. The anomalous Hall conductivity σAH vs longitudinal conductivity σxx characteristics at the corresponding temperatures indicate two AHE mechanisms, which include the side jump and/or intrinsic mechanisms. In addition, the σAH–σxx curve shows obvious changes under different electric fields, which means that the AHE can be mediated. These results are highly important for further understanding of the mechanism by which the electric field can control the AHE.
The half-metallic characteristic of Co2FeAl Huesler alloy films in Co2FeAl/Pb(Mg1/3Nb2/3)O3-PbTiO3 heterostructure was controlled by different substrate temperatures during deposition. The evolution ...of microstructure shows the B2 ordering degree of Co2FeAl thin film increase with the substrate temperature decreasing from 550 °C to 480 °C during deposition, which can be verified by anisotropy magnetoresistance measurement. Moreover, the result measured by rotating-angle ferromagnetic resonance demonstrates B2 ordering degree of Co2FeAl thin film controlled the change of symmetry of magnetic anisotropy. In addition, the loop-like curve of magnetic resonance field/linewidth versus electric field exhibits the non-volatile behavior, which can be attributed to the 109° ferroelectric domain switching of PMN-PT substrate. This result can provide opportunities for magnetization control in multiferroic devices.
•Charge-to-spin conversion can be modulated by the electric field in PMN-PT/LSMO/Py system.•Spin pumping-type and Rashba-type charge-to-spin conversion are observed in the system.•The sign reversal ...of charge-to-spin conversion efficiency can be ascribed to the ferroelectric polarization of PMN-PT.
Modulation of charge-to-spin conversion through active control is supposed to manipulate efficiency in a wide range for future spintronic devices. Despite its great significance, passive control still dominates the manipulation while the active control of charge-to-spin conversion is still challenging. Here we experimentally observe spin pumping-type charge-to-spin conversion besides Rashba-type one in La0.67Sr0.33MnO3 thin films deposited on ferroelectric Pb(Mg1/3Nb2/3)O3–Pb0.7Ti0.3O3 (PMN-PT) substrate. We exhibit that both two types of charge-to-spin conversion efficiency give rise to a variety of sign under positive and negative remnant polarized states of PMN-PT, which can be ascribed to the effect of ferroelectric polarization. The possibility of modulating charge-spin conversion opens a route for designing low-energy spintronics.
•Controllable charge-spin conversion efficiency ξST can be modulated by the thickness of Ta in FeNi/Cu/Ta/MgO.•The greater ξST=0.1038was much larger than Pt, Ta in FeNi/Pt (Ta) systems.•The Ta ...thickness dependence distinctly prove that interface effect in FeNi/Cu/Ta/MgO.
The Rashba-Edelstein effect typically originates from inversion symmetry breaking at an interface that allows charge to spin conversion efficiency comparable to or larger than the SHE. Its potential value is in converting charge current into spin current. Here, we demonstrate experimentally an efficient charge to spin conversion at a Cu/Ta Rashba interface. We exploit spin-torque ferromagnetic resonance to detect a spin current from Cu/Ta interface into adjacent FeNi magnetic layer. The Ta thickness dependence of charge to spin conversion efficiency unambiguously ascribed that interface effect caused FeNi magnetization to precess by generating nonzero spin current that exerts torques rather than bulk effect. The possibility of controllable charge-spin conversion efficiency at room temperature opens another route for modulating the charge to spin conversion by interface engineering.
Abstract
We report spin-orbit torque (SOT) in a single ferrimagnetic (FIM) GdFeCo alloy based on spin-torque ferromagnetic resonance (ST FMR). Thickness-dependent anomalous Hall resistance shows a ...bulk perpendicular magnetic anisotropy, which lead double peaks of ST FMR spectra at a larger thickness of 50 nm. Oblique-angle-dependent ST FMR is performed to study SOT, and the spin torque efficiency in the
y
axis is evaluated. This phenomenon is explained by the relationship between SOT and saturation magnetization. This finding provides an alternative method to modulate SOT in a single ferrimagnetic spintronic device.
•The anti-crossing gap gc enhances 80 Hz by changing the radio frequency (rf) microwave power, which could be ascribed to the enhancement of the dipolar interaction and spin pumping ...effect.•Furthermore, the gc decreases with the increasing angle θ between external magnetic field and rf current due to the increase of the damping.
Magnon-quasiparticle couplings perform magnon information transferences and transports, thus controlling the coupling strengths is significant for novel information function devices. Here, we report the modulation of the magnon-magnon (M−M) coupling strength in Y3Fe5O12/permalloy (YIG/Py) heterostructures via ferromagnetic resonance (FMR) technique. The anti-crossing gap gc enhances 80 Hz by changing the radio frequency (rf) microwave power, which could be ascribed to the enhancement of the dipolar interaction and spin pumping effect. Furthermore, the gc decreases with the increasing angle θ between external magnetic field and rf current due to the increase of magnon relaxation. Moreover, the FMR linewidths change with increasing angle θ due to the magnetic anisotropy parameters and the two-magnon relaxation mechanism induced by the more oblique external field.
PDF
