Formation of quaternary all-d-metal Heusler alloy by Co doping fcc type Ni_(2)MnV and mechanical grinding induced B2–fcc transformation

The structure of the all-d-metal alloy Ni_(50-x)Co_(x)Mn_(25)V_(25)(x=0–50)is investigated by using theoretical and experimental methods.The first-principles calculations indicate that the most stable structure of the Ni_2MnV alloy is face-centered cubic (fcc)type structure with ferrimagnetic state and the equilibrium lattice constant is 3.60A,which is in agreement with the experimental result.It is remarkable that replacing partial Ni with Co can turn the alloy from the fcc structure to the B2-type Heusler structure as Co content x>37 by using the melting spinning method,implying that the d–d hybridization between Co/Mn elements and low-valent elements V stabilizes the Heusler structure.The Curie temperature T_(C) of all-dmetal Heuser alloy Ni_(50-x)Co_(x)Mn_(25)V_(25)(x>37)increases almost linearly with the increase of Co due to that the interaction of Co–Mn is stronger than that of Ni–Mn.A magnetic transition from ferromagnetic state to weak magnetic state accompanying with grinding stress induced transformation from B2 to the dual-phase of B2 and fcc has been observed in these all-d-metal Heusler alloys.This phase transformation and magnetic change provide a guide to overcome the brittleness and make the all-d-metal Heusler alloy interesting in stress and magnetic driving structural transition.

Magnetic skyrmions:materials,manipulation,detection,and applications in spintronic devices

Magnetic skyrmions are vortex-like spin configurations that possess nanometric dimensions,topological stability,and high controllability through various external stimuli.Since their first experimental observation in helimagnet MnSi in 2009,magnetic skyrmions have emerged as a highly promising candidate for carrying information in future high-performance,low-energy-consumption,non-volatile information storage,and logical calculation.In this article,we provide a comprehensive review of the progress made in the field of magnetic skyrmions,specifically in materials,manipulation,detection,and application in spintronic devices.Firstly,we introduce several representative skyrmion material systems,including chiral magnets,magnetic thin films,centrosymmetric materials,and Van der Waals materials.We then discuss various methods for manipulating magnetic skyrmions,such as electric current and electric field,as well as detecting them,mainly through electrical means such as the magnetoresistance effect.Furthermore,we explore device applications based on magnetic skyrmions,such as track memory,logic computing,and neuromorphic devices.Finally,we summarize the challenges faced in skyrmion research and provide future perspectives.