Magnetization and Electrical Resistivity of Erbium Single Crystals

Abstract

The magnetic properties of erbium single crystals (hcp) grown by the Bridgman method have been determined in fields up to 18 kilo-oersteds with the field applied parallel to and perpendicular to the $c$ axis at 4.2\ifmmode^\circ\else\textdegree\fi{}K and between 20.4\ifmmode^\circ\else\textdegree\fi{}K and 300\ifmmode^\circ\else\textdegree\fi{}K. The $c$ axis was found to be the direction of easy magnetization. A N\'eel point was observed at 85\ifmmode^\circ\else\textdegree\fi{}K. The ferromagnetic-antiferromagnetic transition temperature inferred from the magnetic data was 19.6\ifmmode^\circ\else\textdegree\fi{}K. The saturation moment, ${\ensuremath{\sigma}}_{\ensuremath{\infty}0}$, obtained by extrapolation of the $c$-axis data was 8 Bohr magnetons compared to the theoretical 9. Electrical resistivity measurements from 1.3\ifmmode^\circ\else\textdegree\fi{}K to 300\ifmmode^\circ\else\textdegree\fi{}K with the current parallel to the $c$ axis showed a sharp increase in resistivity at 20.4\ifmmode^\circ\else\textdegree\fi{}K, the ferromagnetic-antiferromagnetic transition temperature; a large peak occurred at 53.5\ifmmode^\circ\else\textdegree\fi{}K, and a minimum occurred at the N\'eel point. The $a$-axis resistivity curve showed a change in slope at the N\'eel point and was well behaved elsewhere.