Rawat, Rajdeep Singh

The total current I_total waveform in a plasma focus discharge is the most commonly measured quantity, contrasting with the difficult measurement of I_pinch. However, yield laws should be scaled to focus pinch current I_pinch rather than the peak I_total. This paper describes how I_pinch may be computed from the I_total trace by fitting a computed current trace to the measured current trace using the Lee model. The method is applied to an experiment in which both the I_total trace and the plasma sheath current trace were measured. The result shows good agreement between the values of computed and measured I_pinch.

High energy neutrons, more than 2.45 MeV from deuteron-deuteron fusion reaction, have been measured in backward direction of plasma focus devices in many laboratories. However the experimental evidence for high energy deuterons responsible for such neutrons has not been reported so far. In this brief communication, backward high energy deuteron beam from NX2 plasma focus [M. V. Roshan et al., Phys. Lett. A 373, 851 (2009)] is reported, which was measured with a direct and unambiguous technique of nuclear activation. The relevant nuclear reaction for the target activation is ¹²C (d, n)¹³N , which has a deuteron threshold energy of 328 keV.

Damping-like torque (DLT) arising from the spin Hall effect (SHE) in heavy metals and their alloys has been widely explored for applications in spin–orbit torque MRAM, auto-oscillations, spin waves, and domain wall motion. In conventional materials, the DLT efficiency is limited by intrinsic properties, while attaining strong spin–orbit coupling and higher spin-charge interconversion, with no compromise to electric properties, is the need of the hour. In this Letter, we report more than 3.5 times increase in DLT efficiency, θ_DL, of modified Pt-oxide by employing a better approach of low energy 20 keV O⁺ ion implantation. The highest fluence of O⁺ implantation (1 × 10¹⁷ ions cm⁻²) in Pt enhanced the DLT efficiency from 0.064 to 0.230 and improved the spin transmission for a smaller trade-off in the longitudinal resistivity (𝜌Pt to 𝜌Pt−Oxide) from 55.4 to 159.5 μΩ cm, respectively. The transverse spin Hall resistivity, 𝜌SH, is found to be proportional to the square of the longitudinal resistivity, i.e., 𝜌^impSH∝𝜌²imp, implying that the enhanced SHE in O-implanted Pt is due to a side-jumping mechanism. Further, no break in the twofold as well as mirror symmetry of torques from the O-implanted Pt allows the use of spin-torque ferromagnetic resonance-based line shape analysis to quantify such torques.