Spin-singlet Cooper pairs convert to spin-triplet Cooper pairs on passing through a magnetically noncollinear structure at a superconductor(S)/ ferromagnet(F) interface. In this context, the generation of triplet supercurrents through intrinsic ferromagnetic domain walls, which are naturally occurring noncollinear magnetic features, was proposed theoretically in the past decade. However, an experimental demonstration has been lacking in the literature, particularly because of the difficulty in accessing a single domain wall, which is typically buried between two domains in a ferromagnetic material. By patterning a ferromagnetic nanoconstriction, we have been able to realize a nanoscale S/F/S planar junction, where a single domain wall (pinned at the nanoconstriction) acts as a Josephson barrier. In this geometry, we are able to show the predicted longrange triplet supercurrent across a ferromagnetic barrier exceeding 70 nm. Using this technique, we have demonstrated a ferromagnetic planar nano-SQUID device consisting of two Nb/Ni/Nb spin-triplet Josephson junctions.

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We present a systematic study of the magnetic domain wall induced modulation of superconducting transition temperature (T c ) in Nb/Ni bilayer stripes. By varying the thickness of the Ni layer from 20 nm to 100 nm we have been able to measure the low field T c -H phase diagram spanning the Néel domain wall and Bloch domain wall range of thicknesses. Micromagnetic simulations confirmed a stronger out-of-plane stray field in the Bloch domain walls compared to the Néel walls. A suppression in

Over the last decade, it has been shown that magnetic non-collinearity at an s-wave superconductor/ferromagnet interface is a key ingredient for spin-singlet to spin-triplet pair conversion. This has been verified in several synthetic non-collinear magnetic structures. A magnetically soft and hard ferromagnetic layer combination in a bilayer structure can function as a field tunable non-collinear magnetic structure, which may offer magnetic field tunability of singlet-to-triplet pair conversion. From magnetization measurements of Nb/Co/Py/Nb multilayers, we demonstrate a reversible enhancement of the superconducting critical temperature of 400 mK by measuring Tc with and without a non-collinear magnetic structure between Co and Py. The sensitivity of Tc in these structures offers the potential for realizing magnetic field tunable Josephson junctions in which pair conversion and Josephson critical currents are controllable using modest magnetic fields.

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