Temperature and magnetic field induced multiple magnetic transitions in DyAg2

The magnetic properties of the rare-earth intermetallic compound DyAg2 are studied in detail with the help of magnetization and heat capacity measurements. It is shown that the multiple magnetic phase transitions can be induced in DyAg2 both by temperature and magnetic field. The detailed magnetic phase diagram of DyAg2 is determined experimentally. It was already known that DyAg2 undergoes an incommensurate to commensurate antiferromagnetic phase transition close to 10 K. The present experimental results highlight the first order nature of this phase transition, and show that this transition can be induced by magnetic field as well. It is further shown that another isothermal magnetic field induced transition or metamagnetic transition exhibited by DyAg2 at still lower temperatures is also of first order nature. The multiple magnetic phase transitions in DyAg2 give rise to large peaks in the temperature dependence of the heat capacity below 17 K, which indicates its potential as a magnetic regenerator material for cryocooler related applications. In addition it is found that because of the presence of the temperature and field induced magnetic phase transitions, and because of short range magnetic correlations deep inside the paramagnetic regime, DyAg2 exhibits a fairly large magnetocaloric effect over a wide temperature window, e.g., between 10 and 60 K.