Magnetization reversal and confinement effects across the metamagnetic phase transition in mesoscale FeRh structures

Arregi, Jon Ander; Horký, Michal; Fabianová, Kateřina; Tolley, Robert; Fullerton, Eric E.; Uhlíř, Vojtěch

doi:10.1088/1361-6463/aaaa5a

Cited by 23 publications

(22 citation statements)

References 51 publications

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“…The asymmetries seen in the relaxation behaviour of the heating and cooling branches of the transition is consistent with measurements of the temperature driven domain domains of the system 10,43,[51][52][53] . The physical origin of this imbalance in the nucleation kinetics is unclear.…”

Section: Discussionsupporting

confidence: 84%

Asymmetric magnetic relaxation behavior of domains and domain walls observed through the FeRh first-order metamagnetic phase transition

et al. 2020

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The phase coexistence present through a first-order phase transition means there will be finite regions between the two phases where the structure of the system will vary from one phase to the other, known as a phase boundary wall. This region is said to play an important but unknown role in the dynamics of the first-order phase transitions. Here, by using both x-ray photon correlation spectroscopy and magnetometry techniques to measure the temporal isothermal development at various points through the thermally activated first-order metamagnetic phase transition present in the near-equiatomic FeRh alloy, we are able to isolate the dynamic behavior of the domain walls in this system. These investigations reveal that relaxation behavior of the domain walls changes when phase coexistence is introduced into the system and that the domain wall dynamics is di↵erent to the macroscale behavior. We attribute this to the e↵ect of the exchange coupling between regions of either magnetic phase changing the dynamic properties of domain walls relative to bulk regions of either phase. We also believe this behavior comes from the influence of the phase boundary wall on other magnetic objects in the system.

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Section: Discussionsupporting

confidence: 84%

Asymmetric magnetic relaxation behavior of domains and domain walls observed through the FeRh first-order metamagnetic phase transition

et al. 2020

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“…Electronic transport in FeRh nanowires has been seen to show large supercooling effects and a highly asymmetric transition between heating and cooling 19 . There have been few studies as yet on the effects of lateral confinement of the FeRh layer 20 .…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic-ferromagnetic phase domain development in nanopatterned FeRh islands

Temple

Almeida

Massey

et al. 2018

Phys. Rev. Materials

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The antiferromagnetic to ferromagnetic phase transition in B2-ordered FeRh is imaged in laterally confined nanopatterned islands using photoemission electron microscopy with x-ray magnetic circular dichroism contrast. The resulting magnetic images directly detail the progression in the shape and size of the FM phase domains during heating and cooling through the transition. In 5 µm square islands this domain development during heating is shown to proceed in three distinct modes: nucleation, growth, and merging, each with subsequently greater energy costs. In 0.5 µm islands, which are smaller than the typical final domain size, the growth mode is stunted and the transition temperature was found to be reduced by 20 K. The modification to the transition temperature is found by high resolution scanning transmission electron microscopy to be due to a 100 nm chemically disordered edge grain present as a result of ion implantation damage during the patterning. FeRh has unique possibilities for magnetic memory applications; the inevitable changes to its magnetic properties due to subtractive nanofabrication will need to be addressed in future work in order to progress from sheet films to suitable patterned devices.

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“…In the AFM phase, Fe atoms carry a magnetic moment of 3.3 μ B of alternating direction while the Rh atoms possess inconsiderable magnetic moment 22 . Conversely, in the FM phase, Fe and Rh atoms carry parallel moments of 3.2 μ B and 0.9 μ B , respectively 28 – 30 . This magnetic transition is accompanied with a reduction of the resistivity and an ~ 0.6% isotropic strain of the crystal lattice 21 , 31 .…”

Section: Introductionmentioning

confidence: 99%

Reversible control of magnetism in FeRh thin films

Merkel

Lengyel

Nagy

et al. 2020

Sci Rep

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The multilayer of approximate structure MgO(100)/[ n fe 51 Rh 49 (63 Å)/ 57 fe 51 Rh 49 (46 Å)] 10 deposited at 200 °C is primarily of paramagnetic A1 phase and is fully converted to the magnetic B2 phase by annealing at 300 °C for 60 min. Subsequent irradiation by 120 keV Ne + ions turns the thin film completely to the paramagnetic A1 phase. Repeated annealing at 300 °C for 60 min results in 100% magnetic B2 phase, i.e. a process that appears to be reversible at least twice. The A1 → B2 transformation takes place without any plane-perpendicular diffusion while Ne + irradiation results in significant interlayer mixing. Besides the traditional "faster-smaller-cheaper" directive, a new requirement has recently arisen for the newly developed devices: the energy efficiency. The electricity consumption of information technology is expected to reach 13% of the global utilization in the next decade 1,2 , of which nearly 50% is due to unwanted heat dissipation. Therefore, the study of novel materials and developing new operation principles for energy-saving applications in information technology are essential for supporting sustainable development. From this point of view, the fine control of magnetism is a great step towards reducing energy consumption of information storage by orders of magnitude 3-11. The Fe-Rh system is an excellent playground for developing energy-efficient magnetic devices 12,13. The equilibrium phase diagram of solid Fe-Rh 14,15 includes a great variety of phases of different magnetic behaviour. The disordered bcc A2 (α or δ, prototype W) phases are, depending on temperature, ferro-or paramagnetic (PM). The ordered bcc B2 (α' or α'' , prototype CsCl) phases show ferro-, antiferro-or paramagnetism at different temperatures and concentrations. The disordered fcc A1 (γ, prototype Cu) phase is PM at all investigated temperatures. The existence of a monoclinic antiferromagnetic (AFM) ground state was predicted by DFT calculations in the equiatomic FeRh alloy in 2016 16. However, this phase could not be identified in thin films by Wolloch and co-workers 17. Using nuclear resonant inelastic X-ray scattering (NRIXS), these latter authors analysed the lattice dynamical contribution to the phase stability in FeRh and demonstrated that the AFM ground state was stabilized by phonon softening. With increasing temperature, the nearly equiatomic FeRh alloy of B2 structure undergoes a metamagnetic transition from the low-temperature AFM α'' to the high-temperature ferromagnetic (FM) α' phase close to room temperature (RT) 18-27. In the AFM phase, Fe atoms carry a magnetic moment of 3.3 μ B of alternating direction while the Rh atoms possess inconsiderable magnetic moment 22. Conversely, in the FM phase, Fe and Rh atoms carry parallel moments of 3.2 μ B and 0.9 μ B , respectively 28-30. This magnetic transition is accompanied with a reduction of the resistivity and an ~ 0.6% isotropic strain of the crystal lattice 21,31. By introducing strain in the FeRh crystal lattice, this phenomenon can be reversed and the mag...

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Magnetization reversal and confinement effects across the metamagnetic phase transition in mesoscale FeRh structures

Cited by 23 publications

References 51 publications

Asymmetric magnetic relaxation behavior of domains and domain walls observed through the FeRh first-order metamagnetic phase transition

Asymmetric magnetic relaxation behavior of domains and domain walls observed through the FeRh first-order metamagnetic phase transition

Antiferromagnetic-ferromagnetic phase domain development in nanopatterned FeRh islands

Reversible control of magnetism in FeRh thin films

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