Hopping Crossover and High-Temperature Superspin Glass Behavior in Ni Films Deposited on MoS2

Authors

P. M. Shand, University of Northern IowaFollow
Y. Moua, University of Northern IowaFollow
H. Harms, University of Northern IowaFollow
C. Gorgen, University of Northern IowaFollow
C. J. Cunningham, University of Northern IowaFollow
P. V. Lukashev, University of Northern IowaFollow
T. E. Kidd, University of Northern IowaFollow
A. J. Stollenwerk, University of Northern IowaFollow

Document Type

Article

Keywords

Hopping transport, Magnetoresistance, Magnetic thin films, Spin glasses, Transition metal dichalcogenides, Resistivity measurements, Scanning tunneling spectroscopy

Journal/Book/Conference Title

Physical Review B

Volume

109

Issue

24

Abstract

Realizing the potential of MoS2 and other two-dimensional semiconductors in spintronic devices requires a fundamental understanding of their interaction with ferromagnetic metals. We have investigated the transport and magnetic properties of thin Ni films grown on single-crystal MoS2 substrates. The Ni is found to have a granular morphology with an average grain size of approximately 2 nm. Like previously investigated granular Ni/insulator composites below the percolation threshold, transport is found to proceed via hopping. However, our Ni/MoS2 sample exhibits a dual crossover: activated hopping to T-1/2 variable-range hopping at a higher temperature and then a transition to power-law behavior at a lower temperature. The magnetoresistance was used as a novel probe for uncovering superspin-glass-like behavior above room temperature in the Ni/MoS2 nanostructure, which also exhibits a collective ferromagnetic state at very low temperatures, reminiscent of superferromagnetism.

Department

Department of Physics

Original Publication Date

6-15-2024

DOI of published version

10.1103/PhysRevB.109.245432

Recommended Citation

Shand, P. M.; Moua, Y.; Harms, H.; Gorgen, C.; Cunningham, C. J.; Lukashev, P. V.; Kidd, T. E.; and Stollenwerk, A. J., "Hopping Crossover and High-Temperature Superspin Glass Behavior in Ni Films Deposited on MoS2" (2024). Faculty Publications. 6508.
https://scholarworks.uni.edu/facpub/6508