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arXiv · 2311.05852

Exchange stiffness proportional to power of magnetization in permalloy co-doped with Mo and Cu

Shiho Nakamura·Nobuyuki Umetsu·Michael Quinsat·Masaki Kado
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Abstract

The exchange stiffness of magnetic materials is one of the essential parameters governing magnetic texture and its dynamics in magnetic devices. The effect of single-element doping on exchange stiffness has been investigated for several doping elements for permalloy (NiFe alloy), a soft magnetic material whose soft magnetic properties can be controlled by doping. However, the impact of more practical multi-element doping on the exchange stiffness of permalloy is unknown. This study investigates the typical magnetic properties, including exchange stiffness, of permalloy systematically co-doped with Mo and Cu using broadband ferromagnetic resonance spectroscopy. We find that the exchange stiffness, which decreases with increasing doping levels, is proportional to a power of magnetization, which also decreases with increasing doping levels. The magnetization, $M_{\rm s}$, dependence of the exchange stiffness constant, $A$, of all the investigated samples, irrespective of the doping levels of each element, lies on a single curve expressed as $A\propto M_{\rm s}^n$ with exponent $n$ close to 2. This empirical power-law relationship provides a guideline for predicting unknown exchange stiffness in non-magnetic element-doped permalloy systems.

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Shiho Nakamura, Nobuyuki Umetsu, Michael Quinsat, Masaki Kado. 2023-11-10. Exchange stiffness proportional to power of magnetization in permalloy co-doped with Mo and Cu. https://doi.org/10.1016/j.jmmm.2023.171674

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