Search results for "Anisotropy"

Threshold photoemission magnetic circular dichroism at the spin-reorientation transition of ultrathin epitaxial Pt/Co/Pt(111)/W(110) films

2009

X-ray magnetic circular dichroism (MCD) is nowadays widely used for the investigation of magnetic properties of surfaces and thin films. Recently, similarly large effects have been observed for UV-VIS MCD effects both in single [1] and two-photon photoemission [2-3]. This threshold MCD effect is directly related to spin-orbit effects present at the Fermi edge. We report on the observation of threshold photoemission magnetic circular dichroism (TPMCD) in one-photon and two-photon photoemission (1PPE and 2PPE) at a Pt-capped ultrathin Co wedge grown on Pt(111)/W(110) using femtosecond laser light. TPMCD measurements result in asymmetries continuously increasing with the sample thickness. This…

Magnetic Skyrmions: Current-Induced Skyrmion Generation through Morphological Thermal Transitions in Chiral Ferromagnetic Heterostructures (Adv. Mate…

2018

Torsion oscillation magnetometry (TOM) of Fe films on Ni(111)/W(110) substrates

1999

Abstract Fe films 2–20 atomic monolayers (ML) thick have been deposited on Ni(1 1 1) films (4–60 ML) prepared on W(1 1 0) under UHV conditions. The Ni(1 1 1) films grow in a Nishijama–Wassermann orientation with a 3.6% lattice expansion along Ni[2 1 1] (‖ W[1 1 0]). On top of these slightly distorted Ni films iron is observed to grow preferentially in two mirror orientations. The saturation magnetization of these Fe films and the anisotropies of Fe/Ni bilayers have been studied using torsion oscillation magnetometry. The magnetization of the Fe films of 2.13 μB per atom is close to the bulk value of Fe. The out-of-plane surface (interface) anisotropy constant KFeNis=(−0.65±0.15) mJ/m2 of th…

Large Tunneling Anisotropic Magneto-Seebeck Effect in a CoPt|MgO|Pt Tunnel Junction

2014

We theoretically investigate the Tunneling Anisotropic Magneto-Seebeck effect in a realistically-modeled CoPt|MgO|Pt tunnel junction using coherent transport calculations. For comparison we study the tunneling magneto-Seebeck effect in CoPt|MgO|CoPt as well. We find that the magneto-Seebeck ratio of CoPt|MgO|Pt exceeds that of CoPt|MgO|CoPt for small barrier thicknesses, reaching 175% at room temperature. This result provides a sharp contrast to the magnetoresistance, which behaves oppositely for all barrier thicknesses and differs by one order of magnitude between devices. Here the magnetoresistance results from differences in transmission brought upon by changing the tunnel junction's mag…

Magnetoelectric properties of epitaxialFe3O4thin films on (011) PMN-PT piezosubstrates

2015

We determine the magnetic and magnetotransport properties of 33 nm thick ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ films epitaxially deposited by rf-magnetron sputtering on unpoled (011) ${[{\mathrm{PbMg}}_{1/3}{\mathrm{Nb}}_{2/3}{\mathrm{O}}_{3}]}_{0.68}\ensuremath{-}{[{\mathrm{PbTiO}}_{3}]}_{0.32}$ (PMN-PT) substrates. The magnetoresistance (MR), as well as the magnetization reversal, strongly depend on the in-plane crystallographic direction of the epitaxial (011) ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ film and strain. When the magnetic field is applied along [100], the magnetization loops are slanted and the sign of the longitudinal MR changes from positive to negative around the Verwey transiti…

Role of top and bottom interfaces of a Pt/Co/AlOx system in Dzyaloshinskii-Moriya interaction, interface perpendicular magnetic anisotropy, and magne…

2017

We investigate the role of top and bottom interfaces in inversion symmetry-breaking Pt/Co/AlOx systems by inserting ultra-thin Cu layers. Wedge-type ultrathin Cu layers (0-0.5 nm) are introduced between Pt/Co or Co/AlOx interfaces. Interface sensitive physical quantities such as the interfacial Dzyaloshinskii-Moriya interaction (iDMI) energy density, the interfacial perpendicular magnetic anisotropy (iPMA), and the magneto-optical Kerr effects (MOKE) are systematically measured as a function of Cu-insertion layer thickness. We find that the Cu-insertion layer in the bottom interface (Pt/Co) plays a more important role in iDMI, PMA, and MOKE. In contrast, the top interface (Co/AlOx) noticeab…

Spin Logical and Memory Device Based on the Nonvolatile Ferroelectric Control of the Perpendicular Magnetic Anisotropy in PbZr 0.2 Ti 0.8 O 3 /Co/Pt …

2020

High-pressure structural, lattice dynamics, and electronic properties of beryllium aluminate studied from first-principles theory

2021

Abstract The present work reports the complete study of structural, vibrational, mechanical, and electronic properties of BeAl2O4 (known as Chrysoberyl) using first-principles computing methods. The calculated ground-state properties agree quite well with previous experiments. The computed phonon dispersion curves do not show imaginary frequencies confirming the dynamical stability. In addition, the calculated elastic constants also ensure the mechanical stability through fulfillment of mechanical stability criteria. Apart from that, the theoretically determined phonon frequencies agree quite well with previous Raman and infrared experiments at ambient conditions. Various thermodynamic prop…

Temperature-driven spin reorientation transition inFe∕Mo(110)nanostructures

2007

Using low-temperature spin polarized scanning tunneling microscopy and spectroscopy, we observed a temperature-driven spin-reorientation transition (SRT) in Fe double layer (DL) nanostructures grown by step-flow growth on Mo(110). Magnetization components along the vertical and horizontal directions were detected with $4∕16$ ML Co∕10 ML $\mathrm{Au}∕\mathrm{W}(110)$ tips with out-of-plane (4 ML Co) and in-plane (16 ML Co) magnetic sensitivities. The magnetic easy axis of the Fe DL nanostructures continuously rotates from the vertical direction at $5\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ to an in-plane direction at $20\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The rotation angle is independent …

Spin resolved photoemission study of Co(0001) films

1996

Abstract Thin ferromagnetic films are of great practical interest as they can exhibit a different magnetic behaviour compared to the bulk crystals due to, e.g., the surface anisotropy. The electronic and magnetic properties of thin cobalt films evaporated on W(110) have been investigated by means of angle and spin resolving photoelectron spectroscopy. The study was focused on electron spin polarization, spin resolved intensities and band structure behaviour in dependence of film thickness, excitation energy, and photoelectron detection angle. In order to interpret the experimental results, we have performed relativistic band structure calculations for the Co(0001) surface. The observed agre…