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Giant exchange bias in the single-layered Ruddlesden-Popper perovskite
摘要： Exchange bias (EB) as large as ～5.5 kOe is observed in SrLaCo0.5Mn0.5O4, which is the highest ever found in any layered transition-metal oxides including Ruddlesden-Popper series. Neutron-diffraction measurement rules out long-range magnetic ordering and together with dc magnetic measurements suggests formation of short-range magnetic domains. Ac magnetic susceptibility, magnetic memory effect, and magnetic training effect con?rm the system to be a cluster spin glass. By carrying out density functional calculations on several model con?gurations, we propose that EB is originated at the boundary between Mn-rich antiferromagnetic and Co-rich ferromagnetic domains at the subnanoscale. Reversal of magnetization axis on the Co side alters the magnetic coupling between the interfacial Mn and Co spins, which leads to EB. Our analysis infers that the presence of competing magnetic interactions is suf?cient to induce exchange bias and thereby a wide range of materials exhibiting giant EB can be engineered for designing novel magnetic memory devices.
关键词： Ruddlesden-Popper perovskite,Exchange bias,cluster spin glass,magnetic memory devices
更新于2025-09-23 15:21:21
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Light-induced magnetism in plasmonic gold nanoparticles
摘要： Strategies for the ultrafast optical control of magnetism have been a topic of intense research for several decades because of the potential impact in technologies such as magnetic memory, spintronics and quantum computation, as well as the opportunities for nonlinear optical control and modulation in applications such as optical isolation and non-reciprocity. Here we report experimental quantification of optically induced magnetization in plasmonic gold nanoparticles due to the inverse Faraday effect. The induced magnetic moment is large under typical ultrafast pulse excitation (<1014?W?m?2 peak intensity), with magnetization and demagnetization kinetics that are instantaneous within the subpicosecond time resolution of our study. Our results support a mechanism of coherent transfer of angular momentum from the optical field to the electron gas, and open the door to all-optical sub-wavelength strategies for optical isolation that do not require externally applied magnetic fields.
关键词： ultrafast optical control,quantum computation,inverse Faraday effect,spintronics,magnetic memory,plasmonic gold nanoparticles,light-induced magnetism
更新于2025-09-23 15:19:57