Formation,Magnetic Properties And Magnetic Entropy Change Behavior Of Gd-Ni Binary Alloy And The Magnetic Properties Of Co Addition

The glass forming ability?GFA?,the basic magnetic properties,the magnetocaloric effect?MCE?and the magnetic entropy change of the Gd-Ni and the magnetic properties of addition the Co were investigated in the present work.The following are the details:Firstly,the glass forming ability of the Gd-Ni binary alloys was studid.Phase structure and thermal properties of the ribbons were measured by X-ray diffraction?XRD?and differential scanning calorimetry?DSC?,respectively.The results showed that the Gd₆₈Ni₃₂,Gd₆₅Ni₃₅ and Gd₆₃Ni₃₇ have good glass forming ability.Later,Co element substitution of Ni element in the Gd₆₃Ni₃₇ metallic glass and the amorphous formation ability were studied.which shows that the addition of Co can improve the amorphous forming ability and the thermal stability of the alloy.Secondly,The basic magnetic properties,MCE and the refrigeration capacity?RC?of the Gd_100-xNi_x?x=37,35,32?and Gd₆₃Ni_37-yCo_y?y=2,5,10,12?were surveyed.The results showed that the two series ribbons were typical soft magnetic materials and that they all undergo a second order magnetic phase transition near the Curie temperature?T_c?.The values of magnetic entropy change peak were higher than 9J?kg^-1?K^-1 in all samples,under the field change of 5 T.And,Suitable for magnetic refrigerant.Furthermore,with the increase of Co element,no significant changes of T_c in Gd_100-xNi_x?x=37,35,32?binary alloys can be explained by the 4f-3d exchange interaction between Gd-Ni atoms and the G_K factor.However,the T_c of the Gd₆₃Ni_37-yCo_y?y=2,5,10,12?ternary alloys is tailorable,it will increase with the addition of the Co content.Finally,the magnetic entropy change of the Gd-Ni binary and Gd-Ni-Co ternary amorphous alloys was also studied.The field dependence of magnetic entropy change of the soft magnetic amorphous materials can be expressed as-?S_m?Hⁿ.The experimental results are close to the theoretical value of 0.75 with using the direct method and the method of Kouvel-Fisher.The methods of a master curve provide us an easy way to compare the magnetic entropy change of various materials under different experimental conditions.