Synthesis and Physical Properties of Single Crystal Sb-doped Mn3Sn

• Main Author: RIZKY SIHOMBING (NIM: 20215046), ROMBANG
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30667
• Institution: Institut Teknologi Bandung

<p align="justify">Single crystals Mn3,35Sn1-xSbx (x = 0; 0,03; 0,05; 0,07) have been grown by a simple melting method using a box furnace. Single crystals grown from the cooling process in the temperature range from 1050 oC to 900 oC with a cooling rate of 2,5 oC/h, after that temperature drops naturally to room temperature. The X-ray diffraction characterization shows a single Mn3Sn phase can be obtained for doping concentrations of 0,03, 0,05, and 0,07. Laue diffraction shows a clear single crystal pattern. The refinement using GSAS software show lattice parameters a and c as well the volume decreases as Sb concentration increases. This structure change is caused by the atomic radius Sb (133 pm) smaller than the radius Sn (145 pm). Cooling naturally to room temperature induces a magnetic transition from the helical phase to the spin triangular. The phase transition from helical phase to spin triangular occurs systematically from 270-220 K with increasing Sb concentration. From the magnetic susceptibility data as a function of temperature in the range 300-550 K shows that the Neel temperature drops from 413 K to 407 K with an increase in Sb concentration. The analysis in the paramagnetic region produced an effective moment that expanded from 1,97 µB/Mn to 2,28 µB/Mn but the temperature Weiss decreased from -369,64 K to 318,43 K. From the magnetization curve as a function of the magnetic field shows spontaneous magnetization is increasing at a temperature of 200 K and 300 K with increasing Sb concentration. On the other hand, coercivity does not change with increasing Sb concentration. The curve fitting magnetization data with the molecular field model shows the molecular field constant at a temperature of 200 K higher than 300 K. This indicates the interaction between the sublattices of the helical phase configuration is greater than that of the spin triangular. The change in resistivity to temperature indicates a transition of about 120-140 K related to the end of the helical phase. The resistivity of single crystal Mn3,35Sn1-xSbx (x = 0; 0,03; 0,05; 0,07) as function of temperature can be fitted by using polynomial function up to 5th order. The coefficient which obtained shows the dominant tribe is on the 2nd order polynomial indicates the contribution of the antiferromagnetic metal then the order 5 polynomial coefficient indicates the contribution of the spin wave.<p align="justify">