Effects of Cu Dilution in IrMn on the Exchange Bias ofCoFe/IrMnBilayers

Abstract

The effect of nonmagnetic dilution in metallic antiferromagnets (AFMs) on the exchange bias (EB) has been investigated from a structural, magnetic, and Monte Carlo simulation point of view in bilayers of CoFe/(IrMn)1-xCux. Dilution by Cu atoms throughout the volume of the AFM IrMn gives rise to an enhanced EB field (HEB) for 5 K<or=T<or=350 K. The thermoremanent magnetization of the sole AFM layer is also enhanced with dilution, shows qualitatively the same temperature dependence as HEB, and is at the origin of the EB mechanism. Monte Carlo simulations based on a Heisenberg model and temperature dependent uncompensated AFM moments confirm well the experimental results.

Direct Measurement of Rotatable and Frozen CoO Spins in Exchange Bias System ofCoO/Fe/Ag(001)

“…5). This result shows that the rotatable and frozen spins distribute uniformly inside the entire CoO film, supporting the doping and FM/AFM/FM results [25][26][27][28][29] that the exchange bias depends on the bulk AFM spin structure. It should be mentioned that the NiO spins are much softer than CoO spins due to a much weaker NiO magnetic anisotropy [37].…”

“…The result shows clearly a correlation between the FM and the AFM domains, and the existence of a small amount of uncompensated spins in the AFM layer [19]. It was further shown that only a small percentage of the uncompensated spins is pinned to account for the exchange bias [20,21,22,23] and that these pinned uncompensated AFM spins actually extend into the AFM layer [24], suggesting a bulk-like effect of the AFM spins in the exchange bias [25,26,27,28,29]. Despite the above progress, the compensated AFM spin behavior remains unclear during the FM layer reversal.…”

Focused Kerr measurements on patterned arrays of exchange biased square dots

“…Concerning the grain measurement, different techniques are possible, including rocking curves of x-ray diffraction measurements [12,15], Transmission Electron Microscopy grid scans [11] and AFM measurements [14,16]. We preferred the last method because it is the only one that allows considering grain size distributions deposited on a Si/SiO 2 substrate.…”

Measurement of high frequency conductivity of oxide-doped anti-ferromagnetic thin film with a near-field scanning microwave microscope

“…NSMM is an effective method for characterization of materials, including quantitative dielectric permittivity, [3][4][5][6] sheet resistance or conductivity, 7-10 ferroelectric polarization, 11 permeability 12, 13 and other properties. 14 In this manuscript, we present how the map of high frequency conductivity distribution of an oxide-doped ferromagnetic 19,20 200 nm thin film can be obtained from the quality factor (Q) measured by NSMM. In our calculations, circuit analog approximation was used to determine the electrical properties of the resonator used in NSMM.…”