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

We present magnetic characterization of a binary rare-earth intermetallic compound Er(5)Si(3), crystallizing in Mn(5)Si(3)-type hexagonal structure, through magnetization, heat capacity, electrical resistivity and magnetoresistance measurements. Our investigations confirm that the compound exhibits two magnetic transitions with decreasing temperature, the first one at 35 K and the second one at 15 K. The present results reveal that the second magnetic transition is a disorder-broadened first-order transition, as shown by thermal hysteresis in the measured data. Another important finding is that, below 15 K, there is a magnetic-field-induced transition with a hysteretic effect with the electrical resistance getting unusually enhanced at this transition and the magnetoresistance is found to exhibit intriguing magnetic-field dependence, indicating novel magnetic phase coexistence phenomenon. It thus appears that this compound is characterized by interesting magnetic anomalies in the temperature-magnetic-field phase diagram.