Abstract:Temperature dependence of the tunnel magnetoresistance (TMR) was calculated in range of the quantum-ballistic model in the magnetic tunnel junction (MTJ) with embedded nanoparticles (NPs). The electron tunnel transport through NP was simulated in range of double barrier approach, which was integrated into the model of the magnetic point-like contact. The resonant TMR conditions and temperature impact were explored in detail. Moreover, the possible reasons of the temperature induced resonant conditions were dis… Show more
“…In our previous works 17 – 19 we showed that regime of the quantized conductance due to direct double barrier tunneling ( a = 1) is a main reason of anomalous TMR behaviors, confirming the lack of CB effects for the small NPs, d < 3.5 nm, in these systems. Our basic tunneling approach has similar origin with the theory of giant magnetoresistance in point-like contacts 20 reproducing the limit of the point-like contact when NP touches top and bottom FMLs.…”
Section: Introductionsupporting
confidence: 75%
“…The fraction is defined as a set of TCs with the same size of NPs. The ballistic tunneling was considered as a basic transport approach, and the current for each TC was defined as follows 18 , 19 : Figure 1 Schematic model of the NP-MTJ. Blue and red arrows show parallel (P) and anti-parallel (AP) magnetic configurations, respectively.…”
The problem of the ballistic electron tunneling is considered in magnetic tunnel junction with embedded non-magnetic nanoparticles (NP-MTJ), which creates additional conducting middle layer. The strong temperature impact was found in the system with averaged NP diameter d
av < 1.8 nm. Temperature simulation is consistent with experimental observations showing the transition between dip and classical dome-like tunneling magnetoresistance (TMR) voltage behaviors. The low temperature approach also predicts step-like TMR and quantized in-plane spin transfer torque (STT) effects. The robust asymmetric STT respond is found due to voltage sign inversion in NP-MTJs with barrier asymmetry. Furthermore, it is shown how size distribution of NPs as well as quantization rules modify the spin-current filtering properties of the nanoparticles in ballistic regime. Different quantization rules for the transverse component of the wave vector are considered to overpass the dimensional threshold (d
av ≈ 1.8 nm) between quantum well and bulk-assisted states of the middle layer.
“…In our previous works 17 – 19 we showed that regime of the quantized conductance due to direct double barrier tunneling ( a = 1) is a main reason of anomalous TMR behaviors, confirming the lack of CB effects for the small NPs, d < 3.5 nm, in these systems. Our basic tunneling approach has similar origin with the theory of giant magnetoresistance in point-like contacts 20 reproducing the limit of the point-like contact when NP touches top and bottom FMLs.…”
Section: Introductionsupporting
confidence: 75%
“…The fraction is defined as a set of TCs with the same size of NPs. The ballistic tunneling was considered as a basic transport approach, and the current for each TC was defined as follows 18 , 19 : Figure 1 Schematic model of the NP-MTJ. Blue and red arrows show parallel (P) and anti-parallel (AP) magnetic configurations, respectively.…”
The problem of the ballistic electron tunneling is considered in magnetic tunnel junction with embedded non-magnetic nanoparticles (NP-MTJ), which creates additional conducting middle layer. The strong temperature impact was found in the system with averaged NP diameter d
av < 1.8 nm. Temperature simulation is consistent with experimental observations showing the transition between dip and classical dome-like tunneling magnetoresistance (TMR) voltage behaviors. The low temperature approach also predicts step-like TMR and quantized in-plane spin transfer torque (STT) effects. The robust asymmetric STT respond is found due to voltage sign inversion in NP-MTJs with barrier asymmetry. Furthermore, it is shown how size distribution of NPs as well as quantization rules modify the spin-current filtering properties of the nanoparticles in ballistic regime. Different quantization rules for the transverse component of the wave vector are considered to overpass the dimensional threshold (d
av ≈ 1.8 nm) between quantum well and bulk-assisted states of the middle layer.
“…Some authors have studied the effects associated with the geometric parameters of the domain wall and its dynamics [9][10][11] , the geometry and electronic structure of the contacts 12 , as well as the type of the contact separating area 13,14 . In recent works 15,16 , the behavior of TMR in tunnel junctions with embedded nanoparticles was investigated. The maximum value of TMR in such structures was found to lies close to 300 %.…”
We have studied the influence of the transverse size of a magnetic tunnel nanojunction on the magnitude of the magnetoresistance. During modeling, the size of the right contact was fixed, while the size of the left one gradually changed until they coincided. We found a sharp drop in the tunneling magnetoresistance (TMR) in nanocontacts with mismatched cross section. This can be explained by the peculiarities of the spatial distribution of the electron density, which is different for majority and minority-spin states. The discovered effect must be taken into account in the design of TMR-based nanodevices.
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