Although there has been enormous development in the field of spintronics, it is a challenge to interpret the experimental results and estimate the key parameters e.g., spin diffusion length. While designing functional devices, it creates a severe issue since an inaccurate estimation of one parameter also affects the estimation of other parameters concomitantly. The spin diffusion length of a giant spin-orbit material platinum (Pt) has been reported in literature in a wide range of 0.5 - 14 nm, and it is usually treated as a constant value independent of Pt's thickness. For an accurate estimation of spin diffusion length, noting that circuit theory has been tremendously successful in translating physical equations into circuit elements in organized form, we construct the spin-circuit representation of spin pumping. Thereby it is shown clearly that a thickness-dependent conductivity and spin diffusion length is necessary to simultaneously match the experimental results of effective spin mixing conductance and inverse spin Hall voltage due to spin pumping. Such thickness-dependent spin diffusion length is tantamount to Elliott-Yafet spin relaxation mechanism and it bodes well for transitional metals. It is also shown that this conclusion is not altered when there is a significant interfacial spin memory loss.
The primary impediment to continued improvement of traditional charge-based electronic devices in accordance
with Moore's law is the excessive energy dissipation that takes place in the devices during switching of bits. One
very promising solution is to utilize strain-mediated multiferroic composites, i.e., a magnetostrictive nanomagnet
strain-coupled to a piezoelectric layer, where the magnetization can be switched between its two stable states
in sub-nanosecond delay while expending a minuscule amount of energy of ~1 attojoule at room-temperature.
Apart from devising digital memory and logic, these multiferroic devices can be also utilized for analog signal
processing, e.g., voltage amplifier. First, we briefly review the recent advances on multiferroic straintronic devices
and then we show here that in a magnetostrictive nanomagnet, it is possible to achieve the so-called Landauer
limit (or the ultimate limit) of energy dissipation of amount kT ln(2) compensating the entropy loss, thereby
linking information and thermodynamics.