Disorder influenced magnetic phase transition in the Ce(Fe0.9Ru0.1)2 alloy

We have studied a 10% Ru-doped CeFe2 alloy, Ce(Fe0.9Ru0.1)(2), through magnetization, magnetotransport, and heat capacity measurements. This study shows that, while this alloy is antiferromagnetic at low temperatures and paramagnetic at high temperatures, there exists evidence of ferromagnetic ordering in the intermediate temperature regime. We show here that with 10% Ru doping the first order magnetic transition observed in the Ce(Fe1-xRux)(2) alloys with x < 0.08 is reduced to a quasi-continuous phase transition. The characteristic thermomagnetic history effects associated with the ferromagnetic-antiferromagnetic phase transition in the Ce(Fe1-xRux)(2) alloys with x < 0.08 are not observed in the Ce(Fe0.9Ru0.1)(2) alloy. This alloy continues to exhibit the large magnetoresistance and large magnetocaloric effect associated with this first order magnetic transition in the alloys with smaller Ru concentration, but it does not show any energy loss due to thermomagnetic hysteresis. The present work thus shows how the introduction of quenched disorder due to alloying effects may be used to tune the first order magnetic transition in a material for more efficient functional use.