5 research outputs found
Magnetic properties of hematite revealed by an ab initio parameterized spin model
Hematite is a canted antiferromagnetic insulator, promising for applications
in spintronics. Here, we present ab initio calculations of the tensorial
exchange interactions of hematite and use them to understand its magnetic
properties by parameterizing a semiclassical Heisenberg spin model. Using
atomistic spin dynamics simulations, we calculate the equilibrium properties
and phase transitions of hematite, most notably the Morin transition. The
computed isotropic and Dzyaloshinskii--Moriya interactions result in a N\'eel
temperature and weak ferromagnetic canting angle that are in good agreement
with experimental measurements. Our simulations show how dipole-dipole
interactions act in a delicate balance with first and higher-order on-site
anisotropies to determine the material's magnetic phase. Comparison with
spin-Hall magnetoresistance measurements on a hematite single-crystal reveals
deviations of the critical behavior at low temperatures. Based on a mean-field
model, we argue that these differences result from the quantum nature of the
fluctuations that drive the phase transitions.Comment: 11 pages, 10 figure
Ultrafast coherent all-optical switching of an antiferromagnet with the inverse Faraday effect
We explore the possibility of ultrafast, coherent all-optical magnetization switching in antiferromagnets by studying the action of the inverse Faraday effect in CrPt, an easy-plane antiferromagnet. Using a combination of density-functional theory and atomistic spin dynamics simulations, we show how a circularly polarized laser pulse can switch the order parameter of the antiferromagnet within a few hundred femtoseconds. This nonthermal switching takes place on an elliptical path, driven by the staggered magnetic moments induced by the inverse Faraday effect and leading to reliable switching between two perpendicular magnetic states.publishe
Modular magneto-optical diffractometer for the characterization of magnetoplasmonic crystals
We report on the development of a modular magneto-optical diffractometer designed to measure the optical and magneto-optical properties of nanostructured magnetoplasmonic crystals. The system uses monochromatic, coherent light beams with defined polarization states, for the energy- and angular-dependent measurement of reflected and transmitted beams. Polarization analysis instrumentation further enables the detailed characterisation of the polarization state of the light after the interaction with the magnetoplasmonic crystals. The magneto-optical activity is measured with the help of a quadrupole coil system, allowing for the application of magnetic fields in the plane of the samples. The instrument’s versatile design provides a toolbox of methods capable of capturing a far-field description of the optical and magneto-optical response of magnetoplasmonic crystals. We demonstrate its functionality and utility for the case of a Ni-antidot crystal.
Modular magneto-optical diffractometer for the characterization of magnetoplasmonic crystals
We report on the development of a modular magneto-optical diffractometer designed to measure the optical and magneto-optical properties of nanostructured magnetoplasmonic crystals. The system uses monochromatic, coherent light beams with defined polarization states, for the energy- and angular-dependent measurement of reflected and transmitted beams. Polarization analysis instrumentation further enables the detailed characterisation of the polarization state of the light after the interaction with the magnetoplasmonic crystals. The magneto-optical activity is measured with the help of a quadrupole coil system, allowing for the application of magnetic fields in the plane of the samples. The instrument’s versatile design provides a toolbox of methods capable of capturing a far-field description of the optical and magneto-optical response of magnetoplasmonic crystals. We demonstrate its functionality and utility for the case of a Ni-antidot crystal.
Modular magneto-optical diffractometer for the characterization of magnetoplasmonic crystals
We report on the development of a modular magneto-optical diffractometer designed to measure the optical and magneto-optical properties of nanostructured magnetoplasmonic crystals. The system uses monochromatic, coherent light beams with defined polarization states, for the energy- and angular-dependent measurement of reflected and transmitted beams. Polarization analysis instrumentation further enables the detailed characterisation of the polarization state of the light after the interaction with the magnetoplasmonic crystals. The magneto-optical activity is measured with the help of a quadrupole coil system, allowing for the application of magnetic fields in the plane of the samples. The instrument’s versatile design provides a toolbox of methods capable of capturing a far-field description of the optical and magneto-optical response of magnetoplasmonic crystals. We demonstrate its functionality and utility for the case of a Ni-antidot crystal.