Spin polarization and exchange coupling of Cu and Mn atoms in paramagnetic CuMn diluted alloys induced by a Co layer

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Using the surface, interface, and element specificity of x-ray resonant magnetic scattering in combination with x-ray magnetic circular dichroism, we have spatially resolved the magnetic spin polarization, and the associated interface proximity effect, in a Mn-based high-susceptibility material close to a ferromagnetic Co layer. We have measured the magnetic polarization of Mn and Cu 3d electrons in paramagnetic CuMn alloy layers in ͓Co/ Cu͑x͒ / CuMn/ Cu͑x͔͒ 20 multilayer samples with varying copper layer thicknesses from x =0 to 25 Å. The size of the Mn and Cu L 2,3 edge dichroism shows a decrease in the Mn-induced polarization for increasing copper thickness indicating the dominant interfacial nature of the Cu and Mn spin polarization. The Mn polarization is much higher than that of Cu. Evidently, the Mn moment is a useful probe of the local spin density. Mn atoms appear to be coupled antiferromagnetically with the Co layer below x = 10 Å and ferromagnetically coupled above. In contrast, the interfacial Cu atoms remain ferromagnetically aligned to the Co layer for all thicknesses studied.

Direct Detection of Pure ac Spin Current by X-Ray Pump-Probe Measurements

“…The non-zero XMCD signals (the percentage difference of the XAS for opposite magnetic field directions) at the Ni and Co edges clearly identify the ferromagnetic state of the Py and Co films. The absence of a detectable XMCD signal at the Mn L 3 edge at remanence confirms the nonmagnetic state of the Cu 75 Mn 25 film, showing that the two Cu(3nm) layers completely eliminate any magnetic proximity effect 31 of the Py and Co layers on the Cu 75 Mn 25 layer in our sample. Element-specific hysteresis loop measurements show that while the Py and Co layers exhibit the expected ferromagnetic hysteresis loops, the Cu 75 Mn 25 layer exhibits a paramagnetic linear dependence of the XMCD signal on the magnetic field.…”

“…First, we deduce the Py FMR precession cone angle from the Ni AC and static XMCD magnitudes, 𝜃 𝑁𝑖 = arctan ([ACXMCD(Ni)/[DCXMCD(Ni)]) = arctan (0.2/8)~1.5°. Then using the linear relationship between the XMCD/XAS ratio and the magnetic moment for a Mn atom, 31,52 we find that a Mn AC XMCD signal of 0.02%, as shown in Fig. 3 4(c)] with contributions from all conducting elements in the sample (e.g., the CPW and Cu).…”

Depth-dependent magnetism in epitaxial MnSb thin films: effects of surface passivation and cleaning

“…The sum rules demand that the L 2,3 edges are well separated such that the intensity of the TEY FR can be unambiguously assigned to each L-edge. However, the electrostatic interactions between ionized core levels and valence levels (2p-3d) are of similar magnitude to the spin-orbit coupling of the 2p states, causing jj mixing between the 2p 1/2 and 2p 3/2 channels [34][35][36]. Unambiguous assignment is difficult, although previous studies of elemental Mn on ferromagnetic substrates [35] indicate that the problem can be overcome by multiplying the spin expectation value derived from the sum rules by 1.5.…”

Resonant Soft X-ray Reflectivity in the Study of Magnetic Properties of Low-Dimensional Systems

“…M. Abes et al [40] studied the magnetization of Mn and Cu in a [Co/Cu(x)/CuMn/Cu(x)] multilayer by varying the thickness, x, of the copper layer. Magnetization was induced in the CuMn diluted alloy due to its proximity to the ferromagnetic Co layer.…”