Magnetic Properties of Nd-Fe-B paper graphic
Paper

Magnetic Properties of Nd-Fe-B Single Dots Fabricated Using the PLD–LIFT Method

Volume Number:
17
Publication Date:
Publication Date
January 2026
Author(s)
K. Koike, T. Okawa, Y. Ikagawa, T. Amiya, G. Tahara, M. Itakura, T. Yasunaga, M. Nakano

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Abstract

Single-dot Nd-Fe-B micromagnets were fabricated using the pulsed laser deposition-laser-induced forward transfer (PLD–LIFT) technique, and their magnetic properties were systematically examined. Hysteresis measurements with a vibrating sample magneto meter revealed that the coercivity (Hc) was nearly independent of laser power, whereas an increased defocus rate (DF rate) enhanced Hc up to 340 kA/m. Scanning electron microscopy and cross-sectional scanning transmission electron microscopy analyses revealed that each dot comprises grains ranging from submicrometer to micrometer scale. Within these grains, an Nd2Fe14B core is encapsulated by an Fe-rich matrix containing dispersed Nd oxides. The thickness of this Fe-rich outer shell modifies the exchange pathway at the Nd2Fe14B/Fe interface, giving rise to the characteristic two-step demagnetization. Guided by these observations, a simplified Nd2Fe14B/α-Fe core–shell model was developed and evaluated through micromagnetic simulations, which successfully reproduced the stepwise reversal and clarified DF’s role in suppressing soft-phase connectivity and improving loop squareness. Collectively, these findings identify DF rate as the dominant processing parameter and provide practical guidelines for tailoring PLD–LIFT Nd-Fe-B micromagnets toward microelectromechanical systems applications.