Magnetic anisotropic properties of Pd/Co/Pd trilayer films studied by X-ray absorption spectroscopy and magnetic circular dichroism

Strong perpendicular magnetic anisotropy (PMA) is observed in annealed Pd/Co/Pd trilayer film. The effect of temperature on alloy formation, the relationship among the atomic/electronic structures, magnetic moments and PMA has been studied.

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Revealing noncollinear magnetic ordering at the atomic scale via XMCD

Scientific Reports ◽

10.1038/s41598-021-82518-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Fridtjof Kielgast ◽

Ivan Baev ◽

Torben Beeck ◽

Federico Pressacco ◽

Michael Martins

Keyword(s):

Ground State ◽

Magnetic Circular Dichroism ◽

Magnetic Moments ◽

Magnetic Ordering ◽

Atomic Scale ◽

Angle Of Incidence ◽

X Ray ◽

First Time ◽

X Ray Absorption ◽

Magnetic Sublattices

AbstractMass-selected V and Fe monomers, as well as the heterodimer $${\text{Fe}}_1{\text{V}}_1$$ Fe 1 V 1 , were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.

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Detecting quadrupole: a hidden source of magnetic anisotropy for Manganese alloys

Scientific Reports ◽

10.1038/s41598-020-66432-9 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Jun Okabayashi ◽

Yoshio Miura ◽

Yohei Kota ◽

Kazuya Z. Suzuki ◽

Akimasa Sakuma ◽

...

Keyword(s):

Magnetic Anisotropy ◽

Quantum Physics ◽

Theoretical Calculations ◽

Magnetic Moments ◽

Perpendicular Magnetic Anisotropy ◽

Linear Dichroism ◽

First Principles Calculation ◽

X Ray ◽

Manganese Alloys ◽

Ordered Alloys

Abstract Mn-based alloys exhibit unique properties in the spintronics materials possessing perpendicular magnetic anisotropy (PMA) beyond the Fe and Co-based alloys. It is desired to figure out the quantum physics of PMA inherent to Mn-based alloys, which have never been reported. Here, the origin of PMA in ferrimagnetic Mn3− δ Ga ordered alloys is investigated to resolve antiparallel-coupled Mn sites using x-ray magnetic circular and linear dichroism (XMCD/XMLD) and a first-principles calculation. We found that the contribution of orbital magnetic moments in PMA is small from XMCD and that the finite quadrupole-like orbital distortion through spin-flipped electron hopping is dominant from XMLD and theoretical calculations. These findings suggest that the spin-flipped orbital quadrupole formations originate from the PMA in Mn3− δ Ga and bring the paradigm shift in the researches of PMA materials using x-ray magnetic spectroscopies.

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First principles calculations of intersite disorder influence on the electronic structure and X-ray magnetic circular dichroism in CoFeMnSi Heusler alloy

International Journal of Modern Physics C ◽

10.1142/s0129183120501090 ◽

2020 ◽

Vol 31 (08) ◽

pp. 2050109

Author(s):

S. Uba ◽

A. Bonda ◽

L. Uba ◽

L. V. Bekenov ◽

V. N. Antonov

Keyword(s):

Electronic Structure ◽

Circular Dichroism ◽

First Principles ◽

Heusler Alloy ◽

Magnetic Circular Dichroism ◽

Magnetic Moments ◽

X Ray ◽

The Rich ◽

X Ray Absorption ◽

Circular Dichroïsm

Electronic structure, X-ray absorption, and magnetic circular dichroism (XMCD) spectra in the CoFeMnSi Heusler alloy were studied from first principles. Fully relativistic Dirac linear muffin-tin orbital band structure method was implemented with various exchange–correlation functionals tested. The supercell approach was used to study the influence of intersite disorder, at the levels of 6.25%, 12.5%, and 25% within transition metal sites, on the XMCD spectra at [Formula: see text] edges and spin polarization (SP) at the Fermi level. It is found that most sensitive to Fe–Mn and Co–Fe disorder are XMCD spectra at [Formula: see text] edges of Fe, while the sensitivity decreases from Mn to Co. It is shown that magnetic moments estimated with the use of magneto-optical (MO) sum rules agree with the ab initio calculated ones to within [Formula: see text], [Formula: see text], and [Formula: see text], for Co, Fe, and Mn, respectively. The calculated SP decreases from 99% for ordered CoFeMnSi alloy, to 96% upon 25% Co–Fe disorder, to 83% for Fe–Mn disorder, and to 42% in the case of Co–Mn disorder. The calculated spectra agree well with the available experimental data. The rich XMCD spectral structures are predicted from first principles at Fe, Co, Mn and Si [Formula: see text] edges.

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Martensite Transition and Microscopic Magnetism of Epitaxial Ni2MnGa Films

MRS Proceedings ◽

10.1557/proc-1050-bb08-02 ◽

2007 ◽

Vol 1050 ◽

Cited By ~ 1

Author(s):

Gerhard Jakob ◽

Tobias Eichhorn ◽

Michael Kallmayer ◽

Hans-Joachim Elmers

Keyword(s):

Magnetic Circular Dichroism ◽

Theoretical Calculations ◽

Magnetic Moments ◽

Structural Phase ◽

Absorption Feature ◽

X Ray Diffraction ◽

Orbital Contribution ◽

X Ray ◽

Transmission Geometry ◽

X Ray Absorption

AbstractA magnetically induced shape memory effect in Ni2MnGa results in huge magnetostrictive effects of several percent. Using x-ray absorption spectroscopy (XAS) and magnetic circular dichroism (XMCD) we investigated element specific magnetic moments and electronic structure of single crystalline, (110) oriented Ni2MnGa films on a-plane Al2O3 substrates in the austenite and martensite state. The structural phase transition of the samples is evident from temperature dependent x-ray diffraction and magnetization measurements. The Ni XAS differ significantly for temperatures above and below the martensite transition in agreement with published ab-initio calculations. Using XAS in transmission geometry on our thin film samples we observe the corresponding reduction of the absorption feature as predicted by theoretical calculations. The XMCD analysis shows the orbital contribution of the Ni electrons to be responsible for the magnetic anisotropy.

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XAS and XMCD studies of magnetic properties modifications of Pt/Co/Au and Pt/Co/Pt trilayers induced by Ga+ions irradiation

Journal of Synchrotron Radiation ◽

10.1107/s1600577515002933 ◽

2015 ◽

Vol 22 (3) ◽

pp. 753-759 ◽

Cited By ~ 3

Author(s):

Piotr Mazalski ◽

Iosif Sveklo ◽

Zbigniew Kurant ◽

Katharina Ollefs ◽

Andrei Rogalev ◽

...

Keyword(s):

Ion Irradiation ◽

Magnetic Circular Dichroism ◽

Perpendicular Magnetic Anisotropy ◽

Local Environment ◽

Two Dimensional ◽

High Fluence ◽

X Ray ◽

Plane Anisotropy ◽

X Ray Absorption ◽

Reference Samples

Magnetic and magneto-optical properties of Pt/Co/Au and Pt/Co/Pt trilayers subjected to 30 keV Ga+ion irradiation are compared. In two-dimensional maps of these properties as a function of cobalt thickness and ion fluence, two branches with perpendicular magnetic anisotropy (PMA) for Pt/Co/Pt trilayers are well distinguished. The replacement of the Pt capping layer with Au results in the two branches still being visible but the in-plane anisotropy for the low-fluence branch is suppressed whereas the high-fluence branch displays PMA. The X-ray absorption spectra and X-ray magnetic circular dichroism (XMCD) spectra are discussed and compared with non-irradiated reference samples. The changes of their shapes and peak amplitude, particularly for the high-fluence branch, are related to the modifications of the local environment of Co(Pt) atoms and the etching effects induced by ion irradiation. Additionally, in irradiated trilayers the XMCD measurements at the PtL2,3-edge reveal an increase of the magnetic moment induced in Pt atoms.

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Angle-dependent X-ray magnetic circular dichroism study of enhanced perpendicular magnetic anisotropy in hybrid [CoO/Pd]2[Co/Pd]7 multilayers

Journal of Magnetism and Magnetic Materials ◽

10.1016/j.jmmm.2017.02.019 ◽

2017 ◽

Vol 432 ◽

pp. 450-454 ◽

Cited By ~ 4

Author(s):

D.H. Kim ◽

Eunsook Lee ◽

Hyun Woo Kim ◽

Seungho Seong ◽

Seung-Mo Yang ◽

...

Keyword(s):

Circular Dichroism ◽

Magnetic Anisotropy ◽

Magnetic Circular Dichroism ◽

Perpendicular Magnetic Anisotropy ◽

X Ray ◽

Circular Dichroïsm

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STATE OFCoANDMnIN HALF-METALLIC FERROMAGNETCo2MnSiEXPLORED BY MAGNETIC CIRCULAR DICHROISM IN HARD X-RAY PHOTOELECTRON EMISSION AND SOFT X-RAY ABSORPTION SPECTROSCOPIES

SPIN ◽

10.1142/s2010324714400177 ◽

2014 ◽

Vol 04 (04) ◽

pp. 1440017 ◽

Cited By ~ 8

Author(s):

GERHARD H. FECHER ◽

DANIEL EBKE ◽

SIHAM OUARDI ◽

STEFANO AGRESTINI ◽

CHANG-YANG KUO ◽

...

Keyword(s):

Magnetic Moment ◽

Magnetic Circular Dichroism ◽

Magnetic Moments ◽

Magnetic Behavior ◽

Photoelectron Spectra ◽

X Rays ◽

Half Metallic ◽

X Ray ◽

Magnetic Dichroism ◽

X Ray Absorption

The half-metallic Heusler compound Co2MnSi is a very attractive material for spintronic devices because it exhibits very high tunnelling magnetoresistance ratios. This work reports on a spectroscopic investigation of thin Co2MnSi films as they are used as electrodes in magnetic tunnel junctions. The investigated films exhibit a remanent in-plane magnetization with a magnetic moment of about 5 μBwhen saturated, as expected. The low coercive field of only 4 mT indicates soft magnetic behavior. Magnetic dichroism in emission and absorption was measured at the Co and Mn 2p core levels. The photoelectron spectra were excited by circularly polarized hard X-rays with an energy of 6 keV and taken from the remanently magnetized film. The soft X-ray absorption spectra were taken in an induction field of 4 T. Both methods yielded large dichroism effects. An analysis reveals the localized character of the electrons and magnetic moments attributed to the Mn atoms, whereas the electrons related to the Co atoms contribute an itinerant part to the total magnetic moment.

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