Magnetic behavior of rapidly solidified Pr–Co alloys with the TbCu₇-type structure

Authors

J. Kostogorova, University of Nebraska - Lincoln
Jeffrey E. Shield, University of Nebraska - LincolnFollow

Date of this Version

4-20-2006

Comments

Published by Am Inst of Physics. J. Appl. Phys. 99, 08B514 2006. Copyright 2006. Permission to use. http://www.aip.org/

Abstract

Rapid solidification has been utilized to produce a series of Pr–Co alloys between the Pr₂Co₁₇ and PrCo₅ stoichiometries. In this system, PrCo₅ has easy axis magnetization while Pr₂Co₁₇ has easy-plane magnetization. Alloys of the form (Pr_xCo_1-x)₉₄Ti₃C₃ with x ranging from 0.105 corresponding to the Pr₂Co₁₇ compound tox=0.167 corresponding to the PrCo₅ compound were produced by melt spinning at a tangential wheel speed of 40 m/ s. The rapid solidification and alloying additions were found to suppress the formation of the Pr₂Co₁₇ ordered phase, leading to the formation of the disordered TbCu₇-type structure over a range of Pr/Co ratios. Hysteresis loops were characterized by a smooth demagnetization curve reflective of single-phase demagnetization. Heat treatment at 800 °C led to the formation of the Pr₂Co₁₇ and PrCo₅ phases, and the presence of the soft magnetic Pr₂Co₁₇ phase drastically decreased the coercivity. The soft magnetic behavior was consistent with in-plane magnetization of the Pr₂Co₁₇ structure that formed during heat treatment. However, the relatively high coercivity observed in the as-solidified alloys with the disordered TbCu₇-type structure suggests that dumbbell disorder may create easy axis magnetization, and changes in saturation magnetization also imply that dumbbell configuration is important to the magnetic properties.