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A series of CeMn2(Si1-xGex)2(x = 0.2, 0.4, 0.6, 0.8) compounds are prepared by the arc-melting method. All the samples primarily crystallize in the Th Cr2Si2-type structure. The temperature dependences of zero-field-cooled(ZFC) and FC magnetization measurements show a transition from antiferromagnetic(AFM) state to ferromagnetic(FM) state at room temperature with the increase of the Ge concentration. For x = 0.4, the sample exhibits two kinds of phase transitions with increasing temperature: from AFM to FM and from FM to paramagnetic(PM) at around TN~197 K and T C~300 K,respectively. The corresponding Arrott curves indicate that the AFM–FM transition is of first-order character and the FM–PM transition is of second-order character. Meanwhile, the coexistence of positive and negative magnetic entropy changes can be observed, which are corresponding to the AFM–FM and FM–PM transitions, respectively.
The series of CeMn2 (Si1-xGex) 2 (x = 0.2, 0.4, 0.6, 0.8) compounds were prepared by the arc-melting method. All the samples are crystallized in the Th Cr2Si2- type structure. The temperature dependences of zero- For x = 0.4, the sample exhibits two kinds of phase transitions with room temperature (FSM) Increasing temperature: from AFM to FM and from FM to paramagnetic (PM) at around TN ~ 197 K and TC ~ 300 K, respectively. The corresponding Arrott curves indicate that the AFM-FM transition is first-order character and the FM- PM transition is of second-order character. Meanwhile, the coexistence of positive and negative magnetic entropy changes can be observed, which are corresponding to the AFM-FM and FM-PM transitions, respectively.