A EU-151 MOSSBAUER SPECTROSCOPIC AND MAGNETIC-SUSCEPTIBILITY INVESTIGATION OF THE INTERMETALLIC COMPOUNDS EUTIN (T = ZN, PD, PT, AU)

The title compounds were investigated by magnetic susceptibility measu rements and Eu-151 Mossbauer spectroscopy. EuZnIn and EuPtIn show Curi e-Weiss behavior above 60 K with experimental magnetic moments of 7.80 (5) and 8.0(1) mu(B)/Eu, respectively, indicating divalent europium. T he zinc compound orders antiferromagnetically at T-N = 8.0(5) K and no field induced transition is observed. EuPtIn orders antiferromagnetic ally in small external fields at 16.0(5) K and two metamagnetic transi tions are detected at the critical field strengths B-C1 = 1.1(1) T and B-C2 = 2.6(2) T. At 5 K the saturation magnetic moment amounts to 7.0 (1) mu(B)/Eu, suggesting a full parallel spin alignment. EuPdIn and Eu AuIn order antiferromagnetically at 13.0(5) and 21.0(5) K in low exter nal magnetic fields, respectively. The four compounds are metallic con ductors. The Mossbauer measurements of the EuTIn compounds show (EU)-E -151 isomer shifts typical of divalent europium. The isomer shifts are found to be linearly correlated with the closest Eu-Eu distance in th e structure. Based on the Mossbauer data the onset of magnetic order i s observed at T-N(EuZnIn) = 9.5(5) K, T-N(EuPdIn) 15.5(5) K, T-N(EuAuI n) = 20.0(5) K, and T-N(EuPtIn) = 20.0(5) K, respectively. The magneti cally split spectrum of EuZnIn reveals evidence of Eu site inequivalen ce. (C) 1998 Academic Press.