16464

1735 دكتري

دكتري

ماده چگال تجربي

اصفهان : دانشگاه صنعتي اصفهان

1399

پانزده-105ص.: مصور، جدول، نمودار

حسين احمدوند، هادي سلامتي

پرويز كاملي

علي رستم نژادي، مرتضي مظفري، حميده شاكري پور

1400/03/05

كتابنامه

فيزيك

فيزيك

1400/03/05

2695433

AbstractIn this study firstly we set up a measurement system to measure magnetoelectric voltage inmultiferroic composites We studied the magnetoelectric ME voltage coefficient in theparticulate composite of ferroelectric solid solution 0 94Pb Fe0 5 Nb0 5 O3 0 06PbTiO3 PFN PT with CoFe2O4 CFO and NiFe2O4 NFO ferrites The particulate composites were prepared bymixing the ferrimagnetic and ferroelectric phases with different weight ratios of x 0 05 0 10 0 20 0 30 and 0 40 Ferroelectric magnetic and magnetoelectric properties of the compositeswere studied We investigated the magnetoelectric ME voltage coefficient as a complex quantityfor the first time The results showed that the real part of the ME voltage coefficient is highlyinfluenced by the magnetostrictive phase through the magnetostriction coefficient NFO produceda larger real part of the ME voltage coefficient at a lower magnetic field In the compositescontaining cobalt ferrite the composite with x 0 40 showed the highest magnetoelectriccoefficient Its magnitude was found to be 6 29 mV cmOe at a magnetic field of 1608 Oe with while in the composites containing nickel ferrite the highest magnetoelectric coefficient wasobserved in x 0 30 composite with a magnitude of 10 14 mV cmOe in a magnetic field 209 Oe In the second part single phase 1 x Pb Fe0 5 Nb0 5 O3 x BiFeO3 magnetoelectric solid solutionwas synthesized through solid solution reaction technique with x 0 00 0 10 0 20 and 0 40 TheRietveld refined XRD pattern of x 0 00 confirmed a monoclinic structure with Cm space group while the other samples x 0 10 0 20 and 0 40 showed tetragonal structure with a space groupof P4mm Measurement of dielectric constant versus temperature depicted a transition temperatureof 122 oC for x 0 00 while in the samples containing bismuth the TC value was found to be 74 81 and 191 oC for x 0 10 0 20 and 0 40 respectively Neutron Diffraction magnetization loopand temperature dependence of magnetization exhibited that all the samples haveantiferromagnetic structure The results showed that the Neel magnetic transition temperature TN is increased with the increasing of BiFeO3 Keywords Multiferroics Magnetoelectric Piezoelectric Magnetostrictive Relaxor ferroelectric

حسين احمدوند، هادي سلامتي

پرويز كاملي

علي رستم نژادي، مرتضي مظفري، حميده شاكري پور