The electrical resistivity and Hall effect of Y2Fe14B single crystals have been measured over the temperature range of 4–700 K in magnetic fields of up to 5 T. From these and previous results, which we obtained for Nd2Fe14B and Tm2Fe14B single crystals, we draw some general conclusions about R2Fe14B alloys. The overall behavior of the resistivity is determined mainly by Fe atoms; however, contributions from rare-earth atoms are clearly observed at low temperatures. Large variations of the Hall resistivity are found near the spin reorientation and Curie temperatures. They can be attributed to critical magnetization fluctuations which enhance skew scattering in these regions. We calculate spin fluctuations making use of a phenomenological molecular-field model for an anisotropic ferromagnet. Our calculations account quite well for the observed anomalies in the spontaneous Hall coefficient. Away from the critical regions, side-jump scattering of charge carriers seems to be responsible for the Hall effect.

This work was supported by Project MAT 99-1142 of Comision Interministerial de Ciencia y Tecnología (CICYT).

Peer reviewed