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Enhanced finite size and interface mixing effects in iridium manganese ultra thin films
摘要： The finite size and temperature dependent properties of antiferromagnets are of critical importance to a wide range of spintronic and neuromorphic computing devices. Here we present atomistic simulations of IrMn, one of the most technologically important antiferromagnets, in both the ordered (L12) and disordered (γ) phases. We have found that antiferromagnetic IrMn3 films show a stronger finite size dependence of the Néel temperature than an equivalent ferromagnet due to the existence of spin frustration. We also find that the disordered γ-IrMn3 phase shows a dramatic reduction in the Néel temperature to less than room temperature for films less than 1 nm thick. Interfacial intermixing of the IrMn3 with a non-magnetic Cu capping layer further reduces the Néel temperature for a given film thickness, with a stronger influence on the disordered γ-IrMn3 phase compared to the ordered L12-IrMn3 phase. Our results suggest a larger antiferromagnetic film thickness is required for devices operating at or above room temperature compared to an equivalent ferromagnet, particularly for sputtered films with a high degree of interfacial intermixing.
关键词： Néel temperature,antiferromagnets,neuromorphic computing,IrMn,spintronic devices,finite size effects
更新于2025-09-23 15:21:21
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Annealing effect on laser-induced magnetization dynamics in Co/Ni-based synthetic antiferromagnets with perpendicular magnetic anisotropy
摘要： We report a comprehensive study of annealing treatment modulation on the laser-induced ultrafast magnetic behaviors in antiferromagnetically exchange-coupled [Ni/Co]4/Ru/[Co/Ni]3 multilayers with perpendicular magnetic anisotropy (PMA). Magnetic hysteresis loops indicate that the uniaxial PMA ?eld Hkeff decreases monotonously with the increase in annealing temperature Ta, but the variation of interlayer coupling ?eld Hex is rather complicated. Time-resolved magnetic-optical Kerr effect (MOKE) measurements demonstrate that the laser-excited demagnetization and precession process relies signi?cantly on Ta. Upon laser impulsion, the MOKE signal immediately shows a nonchanging transient increase and decrease with H increasing for low Ta, but only the ultrafast decreasing behavior for high Ta. From the subsequent dynamic precession spectra, the optical and acoustic precession modes are identi?ed. By ?tting the ?eld-dependent frequency curves via the deduced dispersion relations, both Hkeff and Hex are determined and their variation trends agree well with the results from the static magnetic measurement. Moreover, it is found that the critical ?eld where the ultrafast signal decrease occurs is dependent on the co-effect of Hkeff and Hex, whereas the maximum ?eld at which the optical mode precession disappears shares the same trend as Hex. The magnetic damping of acoustic mode is seen to increase with Ta due to the increased inhomogeneities. Our ?ndings provide a deep understanding of the magnetic properties in synthetic antiferromagnetic multilayers with high annealing temperatures, which will be helpful for designing advanced spintronic devices.
关键词： time-resolved magnetic-optical Kerr effect,laser-induced ultrafast magnetic behaviors,annealing treatment,synthetic antiferromagnets,perpendicular magnetic anisotropy
更新于2025-09-16 10:30:52
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Ultrafast Magnetization Reversal in DyFeCo Thin Film by Single Femtosecond Laser Pulse
摘要： The possibility of the local all-optical magnetization reversal in a thin ferrimagnetic rare-earth—transition metal film (DeFeCo) by linearly and circularly polarized 35 fs laser pulses is demonstrated experimentally. Conditions of the exposure to unit pulse and pulse sequence without an applied external magnetic field are used. The found peculiarities of switching in DyFeCo differ substantially from the results obtained previously for rare-earth—transition metal alloys. The minimum nominal fluence for the magnetization reversal is 3 mJ/cm2.
关键词： femtosecond laser,all-optical switching,antiferromagnets
更新于2025-09-16 10:30:52
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - N Anoscale Magnetometry Using Single Spin Quantum Sensors
摘要： Advancing the frontiers of nanoscience and information technology hinges on the availability of novel tools for nanoscale sensing and imaging. Solid-state electronic spins offer a unique platform to implement high-performance quantum sensing devices, which address this need and go beyond what classical technologies offer. We present a robust technology to realise this concept, which is based on nano-engineered diamond devices, hosting single electronic spins for sensing. We will describe the key principles underlying these novel quantum sensors and discuss some of their areas of applications which we have opened over the last years. These include the field of antiferromagnetic spintronics, where single spin magnetometry already yields unprecedented insight into domain formation and non-trivial spin-textures in antiferromagnets. Next to these room-temperature applications, we will present results of cryogenic single spin magnetometry for quantitative, high resolution imaging of vortices and supercurrents in nanoscale superconductors. These examples illustrate the remarkable performance that single spin quantum sensing offers, and which holds great promise for future applications in various applicatons of the nano-sciences.
关键词： scanning probe,spintronics,antiferromagnets,single spins,uncertainty,measurement techniques,Quantum sensing,precision measurements
更新于2025-09-10 09:29:36