Dimorphic cubic phases and magnetic properties of a new binary compound PrIr3

The binary polycrystalline compound PrIr3 is synthesized successfully by arc melting process. The powder X-ray diffraction data reveals that it forms as a macroscopically coexisting dimorphic phases of two different cubic structures (AuBe5- and AuCu3-type). The zero field specific-heat data and dc-magnetization data establishes that while the composition with AuBe5-type structure order ferromagnetically below 12 K, AuCu3-type phase does not show any magnetic order down to the lowest measurement temperature, 2.5 K. The magnetic relaxation, ac magnetization and magnetic memory effect measurement confirms presence of glassy nature in the system which is likely to have originated from the boundary region separating ordered ferromagnetic phase to the paramagnetic phase. As a result, the spin-freezing temperature (TSG∼ 12 K) appear to be very close to the Curie temperature (TC∼ 12 K) in this compound. The critical analysis near second order magnetic phase transition provides accurate magnetic transition temperature as well as helps to identify the universal magnetic class of PrIr3 forming in AuBe5-type structure. The magnetocaloric effect of PrIr3 has been studied from magnetization and specific heat data which reproduce the same values of critical exponents, α, β and γ, although estimated using a different technique.