Abstract
We investigate the emergence of ferromagnetism (FM) in low-Si-content alloys from within the antiferromagnetic (AFM) phase of the parent compound. X-ray magnetic circular dichroism (XMCD) and bulk magnetization measurements show that all samples exhibit partial FM order at low temperature, but their saturation magnetization is reduced relative to higher-Si-content samples . This reduced magnetization is due to an incomplete magnetostructural phase transition upon cooling, as evidenced by x-ray diffraction. High-pressure XMCD measurements in a diamond-anvil cell show that applied pressures of 5.0, 3.0, and 2.0 GPa restore the full saturation magnetization in , 0.05, and 0.075 samples, respectively, by stabilizing the FM-O(I) phase. The mixed-phase behavior is also evidenced in , which strongly varies with silicon concentration in these samples at low pressures but becomes independent of at higher pressures where values typical of higher- samples are found.
1 More- Received 24 October 2008
DOI:https://doi.org/10.1103/PhysRevB.78.214433
©2008 American Physical Society