Thermal expansion anomalies of R2(Fe1−<i>x</i> M<i>x</i>)14B

Abstract

Thermal expansion anomalies of R2(Fe1−xMx)14B (R=Nd and Y; M=Co and Al) have been observed with x-ray powder diffraction in the range from room temperature to 1000 K. All these compounds show an abnormal thermal expansion below the Curie temperature. The substitution effect of Fe by Co and Al on the thermal expansion behavior has been investigated to determine how atomic ordering of these substituent atoms influence the Fe-Fe exchange interactions so as to alter the magnetic properties of the R-Fe-B intermetallic compounds.