Magnetic structure of the Mn5Si3-type Er5Si3 compound

A first-order magnetic phase transition near 15 K with novel magnetic-field-induced effects in Er5Si3

“…We establish the presence of two antiferromagnetic transitions for Er 5 Si 3 , one at 35 K and the other near 15 K. We have shown that the 15K-transition arises from the disorder-broadened first-order phase transition, which is responsible for the magnetic phase-coexistence in the range 10-15 K reported earlier in Ref. 8. There is a magnetic-field-induced transition in the magnetically ordered state; however, below 15 K, there is a hysteresis, both in magnetization as well as in magnetoresistance data, which becomes more prominent with decreasing temperature and an open hysteresis is distinctly observed at very low temperatures.…”

“…All these results conclusively establish that the second transition near 15 K is first-orderlike, however broadened by disorder, thereby explaining the magnetic phase coexistence observed in Ref. 8.…”

“…We show that the second magnetic transition near 15 K is a disorder-broadened first-order magnetic transition, as revealed by hysteresis in the measured data around this transition, thereby resolving the origin of magnetic phase-coexistence inferred in Ref. 8. Another noteworthy finding we report here is that, in the magnetic-field (H) -temperature (T) plane below 15 K, there is a field induced transition, with hysteretic effects, and the shapes of magnetoresistance (MR) versus H plots are rather unique indicating novel magnetic phase-co-existence phenomenon in the H-T phase diagram as well.…”

“…In the data taken with low fields (100 Oe), there is a distinct evidence for two magnetic transitions at 35 and 15 K under all the three measurement conditions. These values of the transition temperature are marginally higher than that reported from neutron diffraction results [8]. Possibly, the transition temperatures could be sample-dependent depending sensitively on the stoichiometry and heat-treatment.…”

“…Due to the presence of two different chemical environments for the two Er atoms, a complex spiral antiferromagnetic (AFM) order sets in at low temperatures. The compound has been reported [8] to exhibit two successive (spiral) antiferromagnetic transitions with decreasing temperature, the first one at 29 K and the other at 13 K with different propagation vectors and it was claimed through neutron diffraction results that there is a narrow temperature interval around 13 K in which two magnetic phases coexist, the reason for which was not obvious. Here, we report an extensive study of this compound through electrical resistivity (ρ), heat capacity (C) and dc magnetization (M) measurements.…”