Metamagnetic phase transitions in ErCo3 investigated with microscopic methods

We studied 59Co nuclear magnetic resonance (NMR) in ErCo3 in magnetic fields up to B0=7 T and at temperatures from 4.2 to 130 K, including the metamagnetic transition at TM=100 K. The hyperfine field Bhf is negative only for the Co 18h-site, at 3b- and 6c-Co it is dominated by an unquenched angular momentum. The temperature dependence of the 18h-Co sublattice magnetization is smaller than deduced in a neutron study, with a first-order step at TM. A rapid decrease in NMR line intensity above ∼40 K may indicate a magnetic instability of 3b-Co