Negative Anisotropic Magnetoresistance in Fe₄N Film

Abstract

Negative anisotropic magnetoresistance (AMR) is observed in Fe4N film from 4.2 to 300 K. The AMR ratio rises with temperature in a stepwise fashion near 50 K, and is accompanied by a change in the magnetization hysteresis. The Campbell and Fert model is extended to investigate the influence of spin-polarization of conduction electrons on the AMR, and it is found that the negative AMR is not observed for majority spin conduction in ferromagnets. Consequently, it is concluded that the negative AMR that observed in the present study is possibly clear evidence of minority spin conduction in Fe4N film, as is predicted theoretically.

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

“…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. 17 Here, s and d represent general conductive and localized electrons, respectively.…”

Planar array of self-assembled GaxFe4−xN nanocrystals in GaN: magnetic anisotropy determinedviaferromagnetic resonance

“…A particularly interesting iron nitride phase is γ′-Fe 4 x − N, due to a high spin polarization of conduction electrons [10][11][12][13] which makes this material well suited for magnetic write heads and as spin injectors in semiconductors [14,15]. On the other hand, gallium-nitride (GaN) and its compounds are not only strategic semiconductors for opto-and high-power-electronics, but-when alloyed with magnetic elements-are emerging as key systems with spintronic functionalities.…”

Deposition and spin polarization study of Fe4N thin films with (111) orientation

“…1 Extensive studies have been performed on the magnetic and transport properties of Fe 4 N after this report. [2][3][4][5][6][7][8][9][10][11][12] The spin polarization of Fe 4 N has been experimentally confirmed by point contact Andreev reflection (PCAR) on a (100) oriented Fe 4 N thin film. 2 Magnetic tunnel junctions (MTJ) with Fe 4 N ferromagnetic electrodes has been reported and their MR ratios are as large as 75% at room temperature.…”

“…3,4 Furthermore, unlike the conventional ferromagnetic electrodes such as CoFeB and CoFe, Fe 4 N has also been predicted and experimentally proved to be a negative spin polarized material. [5][6][7] This characteristic provides a pathway for some novel spin-logic devices. 8,9 To date, most of the spintronics related studies on Fe 4 N are based on epitaxial or polycrystalline thin films with (100) out-of-plane orientation.…”