Biomaterial Database

Direct-Write of Nanoscale Domains with Tunable Metamagnetic Order in FeRh Thin Films. 2021

Cory D Cress, and Darshana Wickramaratne, and Matthew R Rosenberger, and Zachariah Hennighausen, and Patrick G Callahan, and Samuel W LaGasse, and Noam Bernstein, and Olaf M van 't Erve, and Berend T Jonker, and Syed B Qadri, and Joseph C Prestigiacomo, and Marc Currie, and Igor I Mazin, and Steven P Bennett

Electronics Science and Technology Division, United States Naval Research Laboratory, Washington, DC 20375, United States.

We have directly written nanoscale patterns of magnetic ordering in FeRh films using focused helium-ion beam irradiation. By varying the dose, we pattern arrays with metamagnetic transition temperatures that range from the as-grown film temperature to below room temperature. We employ transmission electron microscopy, X-ray diffraction, and temperature-dependent transport measurements to characterize the as-grown film, and magneto-optic Kerr effect imaging to quantify the He+ irradiation-induced changes to the magnetic order. Moreover, we demonstrate temperature-dependent optical microscopy and conductive atomic force microscopy as indirect probes of the metamagnetic transition that are sensitive to the differences in dielectric properties and electrical conductivity, respectively, of FeRh in the antiferromagnetic (AF) and ferromagnetic (FM) states. Using density functional theory, we quantify strain- and defect-induced changes in spin-flip energy to understand their influence on the metamagnetic transition temperature. This work holds promise for in-plane AF-FM spintronic devices, by reducing the need for multiple patterning steps or different materials, and potentially eliminating interfacial polarization losses due to cross material interfacial spin scattering.