First order transition in Dy5Si3Ge: Transport and thermal properties, and first principles calculations

Transport properties of the intermetallic compound Dy5Si3Ge have been studied across its structural and magnetic transitions. The compound has a monoclinic crystal structure at room temperature, and orders magnetically at 74 K (T-N) and 62 K (T-C). Upon cooling it undergoes a structural transition to an orthorhombic structure near T-C. Below similar to 50 K, Dy5Si3Ge exists in a structurally phase separated state and is ferromagnetically ordered. The electrical resistivity and heat capacity of Dy5Si3Ge show interesting hysteretic behavior in the vicinity of the structural transition in zero field. First principles calculations suggest that Ge and Si atoms preferentially occupy intraslab and interslab sites in Dy5Si3Ge, respectively, which leads to dominant ferromagnetic interactions within both the orthorhombic and monoclinic structures. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3554255]