PLD-made anisotropic Nd-Fe-B thick film magnets

Abstract

High-speed PLD (Pulsed Laser Deposition) method with a substrate heating system enabled us to obtain anisotropic Nd-Fe-8 thick film magnets. Coercivity, remanence and (EH),., of the film with the thickness of24 pm were approximately 500 k, 0.75 T and 75 kJ/m, respectively. Experimental In order to compensate loss of metallic Nd due to oxidation, the nominal composition or targets was set to Nd14Fe14B The targets include a larger amount of Nd compared with the stoichiometric composition. These targets were ablated with aNd-YAG pulse laser (3. = 355 nm) at the repetition rate of 30 Hz, and thc distance between a target and a Ta substrate was fixed at IO mm. Thc substrate temperature was varied from 373 to I173 K with a substrate heating system as shown in Fig. 1. In the system, JouIe heat prepared by flowing current in a Ta sheet enabled us to obtain high temperature of the substrate. Before the ablation, the chamber was evacuated down to approximately IO4 Pa with a molecular turbo pump. Duration of the deposition was fixed at 1 h, and a Ti sublimation pump was used as an auxiliary pump during the depositi0n.h-plane and perpendicular M-H loops were measured with a wbrating sample magnetometer (VSM). The analyses of crystal structure were carried out with an X-ray diffractometcr. Thickness was measured with a micrometer