Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 48: Focus Session: Exploiting Spintronics for Unconventional Computing (joint session MA/TT)
TT 48.2: Vortrag
Mittwoch, 14. März 2018, 10:00–10:15, H 1012
Phase domain nucleation and growth investigated in nanofabricated FeRh — •Rowan Temple1, Jamie Massey1, Trevor Almeida2, Kayla Fallon2, Stephen McVitie2, Thomas Moore1, and Christopher Marrows1 — 1University of Leeds, Leeds, UK — 2University of Glasgow, Glasgow, UK
The binary alloy FeRh with B2 (CsCl) chemical ordering displays a magnetostructural phase transition at an unusually high temperature of 350 K. Heating through this point the material undergoes an anti-ferromagnetic (AF) to ferromagnetic (FM) transition, this is accompanied by a 1% volume expansion in the crystal lattice. Being thermodynamically first order in nature, the transition is hysteretic with metastable states coexisting within the material close to the transition temperature. Using nanofabricated epitaxially grown films of FeRh we have examined the effects of rapid thermal heating of this material beyond its equilibrium state. We find decay into equilibrium state is exponential independent of temperature, commensurate with a purely nucleation rather than domain growth driven transition. We have further investigated size dependence of the transition through PEEM imaging and find edge nucleations are key to the transition in a patterned device and lower the expected transition temperature. This understanding will be used to enable the use of patterned FeRh for unconventional computing techniques.