ANOMALOUS MAGNETORESISTANCE NEAR THE METAMAGNETIC TRANSITION IN GD2IN

Gd2In, a layered intermetallic compound, displays two magnetic phase t ransitions below room temperature, the lower one being a metamagnetic transition occurring near 100 K. We have completed measurements of bot h zero-held resistivity for 1.5 less than or equal to T less than or e qual to 300 K and the magnetoresistance in fields of up to 8 T for tem peratures between 1.5 and 120 K; in addition the magnetization has bee n studied in fields up to 5.5 T in the temperature range 2 less than o r equal to T less than or equal to 140 K. As the spin configuration in the ordered phases remains uncertain, these measurements concentrate on the behaviour near the 'ferromagnetic-to-antiferromagnetic' transit ion, and as such they can be compared and contrasted with those report ed recently for Ru-doped CeFe2 in which the spin configurations are be tter known. Plots of the metamagnetic field as a function of temperatu re yield metamagnetic transition temperatures of between 94 and 96 K ( in zero field), in good agreement with earlier estimates. Additional f eatures are observed below 100 K in this system, suggesting difference s between Gd2In and the doped CeFe2 system, originating possibly from fundamental differences in spin structure.