ساخت و بررسي خواص ابررسانايSmBa2Cu3O7-δ آلاييده با نانوذرات Al2O3

Fabrication and Investigation of Superconducting Properties of SmBa2Cu3O7-δ, Doped with Al2O3 Nanoparticles

اﺑﺮرﺳﺎﺗﺎي SmBa2Cu3O7-δ (SBCO) ﺑﺎ اﺳﺘﻔﺎده از روش واﮐﻨﺶ ﺣﺎﻟﺖ ﺟﺎﻣﺪي و ﻫﻢﭼﻨﯿﻦ ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎ )γ-Al2O3( ﺑﻪروش ﺳﻞ- ژل ﺧﻮداﺣﺘﺮاﻗﯽ ﺑﺎ اﻧﺪازة ﻣﺘﻮﺳﻂ 70nm ﺳﺎﺧﺘﻪ و ﺑﺎ ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎي )Al2O3( ﺷﺮﮐﺖ ﺳﯿﮕﻤﺎ ﺑﺎ اﻧﺪازة ﻣﺘﻮﺳﻂ 50nm ﻣﻘﺎﺑﺴﻪ ﺷﺪﻧﺪ. ﺳﭙﺲ اﺑﺮرﺳﺎﻧﺎيSBCO را ﺑﺎ درﺻﺪﻫﺎي ﻣﺨﺘﻠﻒ از ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎ آﻻﯾﺶ داده و ﺧﻮاص آن ﺑﺮرﺳﯽ ﺷﺪﻧﺪ و ﻫﻢﭼﻨﯿﻦ ﺿﺮﯾﺐ اﮐﺴﯿﮋن ﻧﻤﻮﻧﻪﻫﺎي ﺳﺎﺧﺘﻪ ﺷﺪه ﺑﻪروش ﺗﯿﺘﺮاﺳﯿﻮن ﯾﺪﻣﺘﺮي اﻧﺪازهﮔﯿﺮي ﺷﺪ. ﻧﺘﺎﯾﺞ ﺑﻪدﺳﺖ آﻣﺪه ﻧﺸﺎن دادﻧﺪ ﮐﻪ ﺑﺎ آﻻﯾﺶ اﺑﺮرﺳﺎﻧﺎ ﺑﺎ ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎ، ﺿﺮﯾﺐ اﮐﺴﯿﮋن و دﻣﺎي ﺑﺤﺮاﻧﯽ ﻧﻤﻮﻧﻪﻫﺎ ﮐﺎﻫﺶ ﻣﯽﯾﺎﺑﺪ. در ﺑﺮرﺳﯽ ﻧﻤﻮدار ﻣﻘﺎوﻣﺖ وﯾﮋه ﺑﺮ ﺣﺴﺐ دﻣﺎ، ﻧﻤﻮﻧﻪﻫﺎ در ﺣﺎﻟﺖ ﻋﺎدي رﻓﺘﺎر ﻧﯿﻢرﺳﺎﻧﺎﯾﯽ ﻧﺸﺎن دادﻧﺪ، ﯾﻌﻨﯽ ﺑﺎ اﻓﺰاﯾﺶ دﻣﺎ، ﻣﻘﺎوﻣﺖ وﯾﮋه ﮐﺎﻫﺶ ﯾﺎﻓﺖ. ﻫﻢﭼﻨﯿﻦ ﻣﺸﺎﻫﺪه ﺷﺪ ﮐﻪ ﭼﮕﺎﻟﯽ ﺟﺮﯾﺎن ﺑﺤﺮاﻧﯽ ﻧﻤﻮﻧﻪ ﺑﺎ 0/1 درﺻﺪ آﻻﯾﺶ وزﻧﯽ، اﻓﺰاﯾﺶ ﭼﺸﻢﮔﯿﺮي داﺷﺖ، اﻣﺎ ﺑﺎ اﻓﺰاﯾﺶ درﺻﺪ آﻻﯾﺶ ﮐﺎﻫﺶ ﭘﯿﺪا ﮐﺮد. اﻟﮕﻮﻫﺎي ﭘﺮاش اﺷﻌﮥ X ﻧﻤﻮﻧﻪﻫﺎي آﻻﯾﺶ داده ﺷﺪه ﻧﺸﺎن دادﻧﺪ ﮐﻪ ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎ در ﻓﺮاﯾﻨﺪ ﺳﺎﺧﺖ ﺗﺠﺰﯾﻪ ﻧﺸﺪه و در ﻧﺘﯿﺠﻪ در ﺳﺎﺧﺘﺎر ﺑﻠﻮري اﺑﺮرﺳﺎﻧﺎ وارد ﻧﺸﺪهاﻧﺪ. ﺑﺮﺧﯽ از ﻗﻠﻪﻫﺎي اﺑﺮرﺳﺎﻧﺎ در اﻟﮕﻮي ﭘﺮاش اﺷﻌﮥ X ﻧﻤﻮﻧﻪﻫﺎي آﻻﯾﯿﺪه ﺣﺬف ﺷﺪه و ﭘﻬﻨﺎي ﻗﻠﻪﻫﺎ ﻧﺴﺒﺖ ﺑﻪﻧﻤﻮﻧﮥ ﺧﺎﻟﺺ ﺑﯿﺶﺗﺮ ﺷﺪه اﺳﺖ. ﺑﺮرﺳﯽ ﺗﺼﻮﯾﺮﻫﺎي SEM ﻧﻤﻮﻧﻪﻫﺎي آﻻﯾﯿﺪه ﻧﺸﺎن داد ﮐﻪ ﻧﺎﻧﻮذرات آﻟﻮﻣﯿﻨﺎ روي داﻧﻪﻫﺎ و ﻣﺮزداﻧﻪﻫﺎي اﺑﺮرﺳﺎﻧﺎ ﺟﺎي ﮔﺮﻓﺘﻪاﻧﺪ.

SmBa2Cu3O7-δ (SBCO) superconductor is synthesized through the solid state reaction method and also the alumina (γ-Al2O3) nanoparticles with the average size of 70 nm were made through the sol-gel self-combustion method and they were compared with the SIGMA Al2O3 nanoparticles. Then the SBCO superconductor was doped with different percentage of the alumina nanoparticles and its properties were studied and also the oxygen content of the samples was measured by iodometric titration. It was found that the oxygen content and critical temperature of the doped samples reduced. The study of resistivity versus temperature of the samples showed a semiconducting behavior in the normal state; i.e. by increasing the temperature, the resistivity decreased. The critical current density of 0.1 percent doped sample increased significantly, but it decreased by further doping. X-ray diffraction patterns of the doped samples showed that the alumina nanoparticles did not inter into the crystal structure of the superconductor. Also, a few peaks of the X-ray diffraction patterns of the doped samples were absent and the width of the peaks was broadened compared with the undoped sample. SEM images showed that the alumina nanoparticles spread on the surface of the grains and boundaries of the doped samples.