Topological crystalline insulators represent a new state of matter, in which the electronic transport is governed by mirror-symmetry protected Dirac surface states. Due to the helical spin-polarization of these surface states, the proximity of topological crystalline matter to a nearby superconductor is predicted to induce unconventional superconductivity and, thus, to host Majorana physics. We report on the preparation and characterization of Nb-based superconducting quantum interference devices patterned on top of topological crystalline insulator SnTe thin films. The SnTe films show weak anti-localization, and the weak links of the superconducting quantum interference devices (SQUID) exhibit fully gapped proximity-induced superconductivity. Both properties give a coinciding coherence length of 120 nm. The SQUID oscillations induced by a magnetic field show 2π periodicity, possibly dominated by the bulk conductivity.

We investigate the dependence of magnetic properties on the post-annealing temperature/time, the thickness of soft ferromagnetic electrode and Ta dusting layer in the pinned electrode as well as their correlation with the tunnel magnetoresistance ratio, in a series of perpendicular magnetic tunnel junctions of materials sequence Ta/Pd/IrMn/CoFe/Ta(x)/CoFeB/MgO(y)/CoFeB(z)/Ta/Pd. We obtain a large perpendicular exchange bias of 79.6 kA/m for x = 0.3 nm. For stacks with z = 1.05 nm, the magnetic properties of the soft electrode resemble the characteristics of superparamagnetism. For stacks with x = 0.4 nm, y = 2 nm, and z = 1.20 nm, the exchange bias presents a significant decrease at post annealing temperature Tann = 330 • C for 60 min, while the interlayer exchange coupling and the saturation magnetization per unit area sharply decay at Tann = 340 • C for 60 min. Simultaneously, the tunnel magnetoresistance ratio shows a peak of 65.5% after being annealed at Tann = 300 • C for 60 min, with a significant reduction down to 10% for higher annealing temperatures (Tann ≥ 330 • C) and down to 14% for longer annealing times (Tann = 300 • C for 90 min). We attribute the large decrease of tunnel magnetoresistance ratio to the loss of exchange bias in the pinned electrode.

Herein, sputter‐deposited ferromagnetic Weyl semimetal (WSM) and full‐Heusler compound Co2TiGe is investigated. Crystal quality is analyzed using X‐ray diffraction and reflectivity. In addition, temperature‐dependent transport and magnetization measurements are carried out. The sample shows indications on the formation of L21 crystal structure. Magnetization measurements show a saturation magnetization of 1.98 μB (f.u.)−1 and 1.45 μB (f.u.)−1 at 50 and 300 K, respectively. This is in close agreement to the calculated value of 2 μB (f.u.)−1 at 0 K using the Slater–Pauling rule. The obtained Curie temperature is 378.5 K, which is close to prior results for bulk samples. The residual resistivity of 142.7 μΩ cm is mainly dominated by disorder scattering. At temperatures above 60 K, the Coulomb interaction dominates the resistance. The residual resistance ratio is around 1.49. Hall measurements show positive ordinary Hall and anomalous Hall constants and a positive dependence on temperature. Skew scattering and side jumps or intrinsic mechanisms contribute in similar amounts to the anomalous Hall resistivity, which indicates a higher than usual intrinsic contribution, which is expected for WSMs. The expected relation between the longitudinal and the anomalous Hall conductivity of is not met.

The manifestation of spin-orbit interactions, long known to dramatically affect the band structure of heavy-element compounds, governs the physics in the surging class of topological matter. A particular example is found in the new family of topological crystalline insulators. In this systems transport occurs at the surfaces and spin-momentum locking yields crystal-symmetry protected spin-polarized transport. We investigated the current-phase relation of SnTe thin films connected to superconducting electrodes to form SQUID devices. Our results demonstrate that an assisting in-plane magnetic field component can induce 0-π-transitions. We attribute these findings to giant g-factors and large spin-orbit coupling of SnTe topological crystalline insulator, which provides a new platform for investigation of the interplay between spin-orbit physics and topological transport.

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