Negative spin polarization at the Fermi level in Fe4N epitaxial films by spin-resolved photoelectron spectroscopy

Kabara

Sanai

et al. 2014

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Section: Introductionsupporting

confidence: 87%

Section: Experimental Methodsmentioning

confidence: 70%

Sign of the spin-polarization in cobalt-iron nitride films determined by the anisotropic magnetoresistance effect

Kabara

Sanai

et al. 2014

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“…12 Furthermore, spin-resolved photoemission spectroscopy study revealed the negative P D near E F for Fe 4 N films on STO(001) substrate. 13 Recently, a negative anisotropic magnetoresistance (AMR) effect was reported for Fe 4 N films. [14][15][16] To clarify the observed AMR, Kokado et al performed a model calculation and exhibited relationship between the sign of AMR signals and dominant s-d scattering process in ferromagnetic materials.…”

Section: Introductionmentioning

confidence: 99%

Local electronic states of Fe4N films revealed by x-ray absorption spectroscopy and x-ray magnetic circular dichroism

Toko

Takeda

et al. 2015

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We performed x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) measurements at Fe L2,3 and N K-edges for Fe4N epitaxial films grown by molecular beam epitaxy. In order to clarify the element specific local electronic structure of Fe4N, we compared experimentally obtained XAS and XMCD spectra with those simulated by a combination of a first-principles calculation and Fermi's golden rule. We revealed that the shoulders observed at Fe L2,3-edges in the XAS and XMCD spectra were due to the electric dipole transition from the Fe 2p core-level to the hybridization state generated by σ* anti-bonding between the orbitals of N 2p at the body-centered site and Fe 3d on the face-centered (II) sites. Thus, the observed shoulders were attributed to the local electronic structure of Fe atoms at II sites. As to the N K-edge, the line shape of the obtained spectra was explained by the dipole transition from the N 1s core-level to the hybridization state formed by π* and σ* anti-bondings between the Fe 3d and N 2p orbitals. This hybridization plays an important role in featuring the electronic structures and physical properties of Fe4N.

“…Several reports have presented the AMR ratio of Fe 4 N, reporting ratios of À2.7% at 5 K, 13 À4.3% at 4.2 K, 14 and À6.2% at 4 K. 15 The negative sign of the P D has been anticipated by theory 16 and has been confirmed by experiments using spin-resolved photoelectron spectroscopy. 17 Another report on the inverse tunnel magnetoresistance effect in the Fe 4 N/MgO/CoFeB magnetic tunnel junction structure has also suggested that a negative P D is present in Fe 4 N. 19 For ferromagnetic thin films with perpendicular magnetic anisotropy (PMA), CIDM can be detected by various methods such as direct observation using the magnetooptical Kerr effect [20][21][22] and electrical measurement using the anomalous Hall effect. [23][24][25][26] For materials with in-plane magnetic anisotropy (IMA), on the other hand, the DW motion is Published by AIP Publishing.…”

Section: Introductionmentioning

confidence: 99%

“…12 The negative sign of the P r has been deduced from the negative anisotropic magnetoresistance (AMR) ratio, [13][14][15] and from the negative spin polarization of the density of states (D) at the Fermi level (E F ), P D . This spin polarization of the density of states is given by 16,17 and the relation that the AMR ratio is proportional to ÀP r P D is used. 18 The AMR ratio is given by…”

Section: Introductionmentioning

confidence: 99%

Electrical detection of magnetic domain wall in Fe4N nanostrip by negative anisotropic magnetoresistance effect

Gushi

Higashikozono

et al. 2016

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The magnetic structure of the domain wall (DW) of a 30-nm-thick Fe4N epitaxial film with a negative spin polarization of the electrical conductivity is observed by magnetic force microscopy and is well explained by micromagnetic simulation. The Fe4N film is grown by molecular beam epitaxy on a SrTiO3(001) substrate and processed into arc-shaped ferromagnetic nanostrips 0.3 μm wide by electron beam lithography and reactive ion etching with Cl2 and BCl3 plasma. Two electrodes mounted approximately 12 μm apart on the nanostrip register an electrical resistance at 8 K. By changing the direction of an external magnetic field (0.2 T), the presence or absence of a DW positioned in the nanostrip between the two electrodes can be controlled. The resistance is increased by approximately 0.5 Ω when the DW is located between the electrodes, which signifies the negative anisotropic magnetoresistance effect of Fe4N. The electrical detection of the resistance change is an important step toward the electrical detection of current-induced DW motion in Fe4N.