Domain wall induced modulation of low field H-T phase diagram in patterned superconductor-ferromagnet stripes

Bhatia, Ekta; Barber, Z. H.; Maasilta, I. J.; Senapati, Kartik

doi:10.1063/1.5087925

Cited by 6 publications

(5 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in thin films, while decreasing magnetic field from saturation value, the domain formation starts well before the magnetic field reaches zero and as a result the magnetization decreases from the saturation value. In our Ni thin films the domain formation starts around +0.1 T while decreasing magnetic field from positive saturation as reported earlier [29]. Figure 3(d) shows the same feature while ramping the field from negative saturation toward positive saturation.…”

Section: Magneto-transport Below Superconducting Transition Temperatu...supporting

confidence: 85%

“…Since this measurement was done very close to the superconducting transition, the Nb layer is expected to respond to DW stray fields very sensitively. Therefore, the origin of MR peaks observed at this temperature is the usual suppression of superconductivity due to the out of plane component of DWs present in nickel as observed in earlier reports [28,29]. Since the overall DW stray field maximizes near the coercive field, the MR peaks, in this case appear near the coercive field.…”

Section: Magneto-transport Below Superconducting Transition Temperatu...supporting

confidence: 75%

See 1 more Smart Citation

Unconventional domain wall magnetoresistance of patterned Ni/Nb bilayer structures below superconducting transition temperature of Nb

Bhatia

Hussain

Reddy

et al. 2021

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

Scattering of spin-up and spin-down electrons while passing through a ferromagnetic domain wall (DW) leads to an additional resistance for transport current, usually observed prominently in constricted magnetic structures. In this report we use the resistance of the DW as a probe to find an indirect signatures of the theoretically predicted spin-singlet supercurrent to spin-triplet supercurrent conversion effect of ferromagnetic DWs. Here we examine the DW induced resistance in Ni stripe in a bilayer Ni/Nb geometry in the normal state and in the superconducting state of Nb. By making a 3 μm wide gap in the top Nb layer we routed the transport current through the Ni layer in the normal state and in the superconducting state of Nb. In the normal state of Nb, in-field transport measurements showed a clear domain wall magneto-resistance (DWMR) peak of amplitude ∼5.9 mΩ near the coercive field, where the DW density is expected to be maximum. Interestingly, however, below the superconducting transition temperature of Nb, the DWMR peak of the Ni layer showed a sharp drop in the field range where the number of DWs become maximum. This observation may be a possible signature of magnetic DW induced spin-triplet correlations in the Ni layer due to the direct injection of spin-singlet Cooper pairs from Nb into the magnetic DWs.

show abstract

Section: Magneto-transport Below Superconducting Transition Temperatu...supporting

confidence: 85%

Section: Magneto-transport Below Superconducting Transition Temperatu...supporting

confidence: 75%

Unconventional domain wall magnetoresistance of patterned Ni/Nb bilayer structures below superconducting transition temperature of Nb

Bhatia

Hussain

Reddy

et al. 2021

J. Phys.: Condens. Matter

Self Cite

View full text Add to dashboard Cite

show abstract

“…Such pwave superconductivity offers spin and orbital degrees of freedom. We note that spintriplet Cooper pairs with odd-parity s-wave symmetry can be generated at an interface between an s-wave superconductor (SC) and a ferromagnet (F) [3,4]-for example, spinmixing due to the ferromagnetic exchange field generates m = 0 spin-triplet Cooper pairs, and broken spin-rotational symmetry converts m = 0 triplets into equal spin m = ±1 triplet pairs [5][6][7][8][9][10][11][12][13][14]. Moreover, broken inversion symmetry at an SC/F interface generates spin-orbit coupling (SOC), which creates interfacial spin-triplet superconductivity [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

A Review of Electronic Transport in Superconducting Sr2RuO4 Junctions

Anwar¹,

Robinson²

2021

Coatings

View full text Add to dashboard Cite

We review electronic transport in superconducting junctions with Sr2RuO4. Transport measurements provide evidence for chiral domain walls and, therefore, chiral superconductivity in superconducting Sr2RuO4, but so far, the symmetry of the underlying superconducting state remains inconclusive. Further studies involving density of states measurements and spin-polarised transport in local/non-local Sr2RuO4 junctions with magnetic materials could lead to fundamental discoveries and a better understanding of the superconducting state.

show abstract

“…Figure 6(b) shows that dM/dH increases sharply below 20 Oe as the applied magnetic field is reduced from positive saturation, indicating the nucleation of domain walls in Py. Domain walls are known to reduce the transition temperature in S/F structures by an amount proportional to the domain density [36]. Around a field of +15 Oe the dM/dH starts to decrease sharply indicating the beginning of the rotation of the Py layer and the consequent drop in total moment.…”

Section: Resultsmentioning

confidence: 99%

Aspects of long range spin–triplet correlations in superconductor/ferromagnet hetero-structures

Bhatia¹,

Senapati²

2022

Supercond. Sci. Technol.

Self Cite

View full text Add to dashboard Cite

The notion of competing ferromagnetic(F) and superconducting(S) orders in F/S hybrid structures was transformed by the first realization of ferromagnetic Josephson π-junctions and the almost simultaneous prediction of a possibility of spin- triplet correlations in such structures, almost two decades back. F/S hybrid structures in various configurations are now studied as rich sources of emergent states and new effects. Unlike the spin singlet Cooper pairs, the spin triplet Cooper pairs are much less affected by the exchange field of a ferromagnet and, therefore, immediately finds interest in the field of spintronics. Theoretically it has been shown that the basic protocol for spin-singlet to spin-triplet supercurrent conversion is the presence of magnetic non-collinearity at the superconductor-ferromagnet interface. Therefore, almost all experiments in this direction have utilized transport measurements on F/S systems with artificial magnetic non-collinearity formed by combination of several ferromagnetic layers next to the superconducting layer. Here we highlight two aspects of studying these heterostructures. Firstly we show that natural magnetic inhomogeneities, found in domain walls of ferromagnets, can also be used to achieve singlet-triplet conversion, instead of artificial magnetic inhomoheneities. This possibility was explored via transport measurements in nano-scale planar Nb-Ni- Nb junctions and nano-SQUIDs, where a domain wall was pinned at the Josephson junction barrier. By this method we were able to show Josephson coupling across about 70 nm of strong ferromagnetic planar barrier. Secondly we show that spin-triplet correlations at the F/S interface are robust enough to be probed by the diamagnetic screening currents at the interface. This was probed by studying the change in sperconducting transition temperature of Nb/Co/Py/Nb multilayers in presence of small in-plane magnetic field. The Co/Py combination, which is a soft-hard type magnetic exchange spring, worked as magnetic inhomogeneity for triplet generation at the interface of the superconducting Nb.

show abstract

Domain wall induced modulation of low field H-T phase diagram in patterned superconductor-ferromagnet stripes

Cited by 6 publications

References 35 publications

Unconventional domain wall magnetoresistance of patterned Ni/Nb bilayer structures below superconducting transition temperature of Nb

Unconventional domain wall magnetoresistance of patterned Ni/Nb bilayer structures below superconducting transition temperature of Nb

A Review of Electronic Transport in Superconducting Sr2RuO4 Junctions

Aspects of long range spin–triplet correlations in superconductor/ferromagnet hetero-structures

Contact Info

Product

Resources

About